Antenatal interventions for reducing weight in obese women The Cochrane Library

Transcription

Antenatal interventions for reducing weight in obese women
for improving pregnancy outcome (Review)
Furber CM, McGowan L, Bower P, Kontopantelis E, Quenby S, Lavender T
This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library
2013, Issue 1
http://www.thecochranelibrary.com
Antenatal interventions for reducing weight in obese women for improving pregnancy outcome (Review)
Copyright © 2013 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
TABLE OF CONTENTS
HEADER . . . . . . . . . . . . . . . . . .
ABSTRACT . . . . . . . . . . . . . . . . .
PLAIN LANGUAGE SUMMARY . . . . . . . . .
BACKGROUND . . . . . . . . . . . . . . .
OBJECTIVES . . . . . . . . . . . . . . . .
METHODS . . . . . . . . . . . . . . . . .
RESULTS . . . . . . . . . . . . . . . . . .
DISCUSSION . . . . . . . . . . . . . . . .
AUTHORS’ CONCLUSIONS . . . . . . . . . .
ACKNOWLEDGEMENTS
. . . . . . . . . . .
REFERENCES . . . . . . . . . . . . . . . .
CHARACTERISTICS OF STUDIES . . . . . . . .
DATA AND ANALYSES . . . . . . . . . . . . .
APPENDICES . . . . . . . . . . . . . . . .
CONTRIBUTIONS OF AUTHORS . . . . . . . .
DECLARATIONS OF INTEREST . . . . . . . . .
SOURCES OF SUPPORT . . . . . . . . . . . .
DIFFERENCES BETWEEN PROTOCOL AND REVIEW
INDEX TERMS
. . . . . . . . . . . . . . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
1
1
2
2
5
6
7
7
7
8
8
14
23
23
26
26
27
27
27
i
[Intervention Review]
Antenatal interventions for reducing weight in obese women
for improving pregnancy outcome
Christine M Furber1 , Linda McGowan1 , Peter Bower2 , Evangelos Kontopantelis3 , Siobhan Quenby4 , Tina Lavender1
1 School
of Nursing, Midwifery and Social Work, The University of Manchester, Manchester, UK. 2 NIHR School for Primary Care
Research, Manchester Academic Health Science Centre, Institute of Population Health, University of Manchester, Manchester, UK.
3 Health Sciences Primary Care Research Group, The University of Manchester, Manchester, UK. 4 Clinical Sciences Research Institute,
University of Warwick, Coventry, UK
Contact address: Christine M Furber, School of Nursing, Midwifery and Social Work, The University of Manchester, Jean McFarlane
Building, Oxford Road, Manchester, M13 9PL, UK. [email protected].
Editorial group: Cochrane Pregnancy and Childbirth Group.
Publication status and date: New, published in Issue 1, 2013.
Review content assessed as up-to-date: 16 November 2012.
Citation: Furber CM, McGowan L, Bower P, Kontopantelis E, Quenby S, Lavender T. Antenatal interventions for reducing weight in
obese women for improving pregnancy outcome. Cochrane Database of Systematic Reviews 2013, Issue 1. Art. No.: CD009334. DOI:
10.1002/14651858.CD009334.pub2.
ABSTRACT
Background
Being obese and pregnant is associated with substantial risks for the mother and her child. Current weight management guidance for
obese pregnant women is limited. The latest recommendations suggest that obese pregnant women should gain between 5.0 and 9.1
kg during the pregnancy period, and weight loss is discouraged. However, observational studies indicate that some obese pregnant
women, especially those who are heavier, lose weight during pregnancy. Furthermore, some obese pregnant women may intentionally
lose weight. The safety of weight loss when pregnant and obese is not substantiated; some observational studies suggest that risks
associated with weight loss such as pre-eclampsia are improved, but others indicate that the incidence of small- for-gestational infants
are increased. It is important to evaluate interventions that are designed to reduce weight in obese pregnant women so that the safety
of weight loss during this period can be established.
Objectives
To evaluate the effectiveness of interventions that reduce weight in obese pregnant women.
Search methods
We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (31 July 2012) and contacted experts in the field.
Selection criteria
Randomised controlled trials, ’quasi-random’ studies and cluster-randomised trials comparing a weight-loss intervention with routine
care or more than one weight loss intervention. Cross-over trials were not eligible for inclusion.
Data collection and analysis
We identified no studies that met the inclusion criteria for this review.
Main results
There were no included trials.
1
Authors’ conclusions
There are no trials designed to reduce weight in obese pregnant women. Until the safety of weight loss in obese pregnant women
can be established, there can be no practice recommendations for these women to intentionally lose weight during the pregnancy
period. Further study is required to explore the potential benefits, or harm, of weight loss in pregnancy when obese before weight loss
interventions in pregnancy can be designed. Qualitative research is also required to explore dietary habits of obese pregnant women,
especially those who are morbidly obese.
PLAIN LANGUAGE SUMMARY
Trials of interventions for pregnant women who are obese to lose weight and improve pregnancy outcomes.
Pregnant women who are obese risk serious complications for themselves and their children. The mother is more likely to develop
diabetes or high blood pressure or pre-eclampsia during pregnancy, and the pregnancy may end in a miscarriage or stillbirth. The baby
could have serious anomalies at birth, including spina bifida, cardiovascular anomalies, cleft lip and palate, or limb reduction anomalies.
Some obese women have premature births. At birth, the labour may be longer and other complications can lead to a caesarean birth.
The baby may also be bigger at birth than is normal, and there is evidence that the children of obese mothers go on to be obese. The
advice for obese women in managing their weight during pregnancy is that weight loss should be avoided, and weight gain should be
between 5.0 and 9.1 kg. Yet observational studies of large numbers of pregnant women indicate that some obese women, especially
those who are heavier, lose weight during pregnancy. We do not have any clear results that indicate that losing weight when pregnant
is safe for a mother who is obese, or for her baby. This Cochrane review aimed to evaluate trials that were designed for obese pregnant
women to lose weight. No randomised controlled trials were found. We recommend that further research is conducted to evaluate the
safety of interventions for weight loss when a woman is pregnant and obese for the mother and her baby.
BACKGROUND
Description of the condition
Obesity is defined as ’abnormal or excessive fat accumulation that
may impair health’ (World Health Organization 2006). The prevalence of obesity is now at epidemic proportions, and is one of the
most important challenges of the 21st century.
Body mass index (BMI) is commonly used to measure an individual’s weight in relation to their height. It is expressed as
body weight (kg) divided by the square of height (m²). A calculation of 18.5 to 24.9 (kg/m²) is desirable (normal weight),
whereas 25 to 29.9 (kg/m²) is ’overweight’, 30 (kg/m²) or above is
’obese’ (Zaninotto 2006). The World Health Organization (World
Health Organization 2000) has further classified obesity as:
• BMI 30 to 34.9 (kg/m²) - class I obesity;
• BMI 35.0 to 39.9 (kg/m²) - class II or severe obesity;
• BMI 40 (kg/m²) and above - class III or morbid obesity.
The risks related to being obese at the start of pregnancy are substantial, and may involve the pregnancy, birth, and later life for
both the woman and her infant.
Risks in pregnancy for obese women
Compared to normal-weight women, obese women are more at
risk of pregnancies affected by congenital anomalies, including
spina bifida, cardiovascular anomalies, cleft lip and palate, and
limb reduction anomalies (Rankin 2010; Stothard 2009). Stillbirth is also more common (Chu 2007; Flenady 2011; Ovesen
2011) and there is a possibility that miscarriage is more likely
in obese women (Metwally 2008). Several studies suggest that
gestational diabetes, hypertension, and pre-eclampsia/eclampsia
are common pregnancy complications when obese (Baeton 2001;
Doherty 2006; Ovesen 2011; Sebire 2001). Also, around one-fifth
of women who are obese at the start of the pregnancy give birth to
large (macrosomic) babies (defined as greater than 4000 g or larger
than 90th centile) (Baeton 2001; Sebire 2001; Zhang 2007).
Risks during birth for obese women
The pregnancies of obese women are longer, and prolonged gestation may lead to complications at birth. Data from the Danish Birth cohort from 1996 to 2004 indicate that post-term birth
(pregnancy length longer than 294 days) is correlated with higher
pre-pregnancy BMI Oleson 2006. In clinical practice, prolonged
2
pregnancies are more likely to be induced (Doherty 2008), and
inductions may be unsuccessful when obese (Kerrigan 2009).
Caesarean births are more frequent in women who are obese.
Heslehurst 2008 carried out a systematic review of the impact of
BMI on pregnancy outcomes. The results indicate significantly
reduced odds for vaginal birth when overweight, and obese. These
results are corroborated with the analysis of Danish births from
2004 to 2010 as those obese, and morbidly obese, were more likely
to give birth by planned or emergency caesarean section (Ovesen
2011). Operative birth assistance is needed more often for delays
in labour when obese and compared with normal-weight women
(Kerrigan 2009; Zhang 2007). Fetal distress in labour has also been
reported as more likely, and a reason for emergency caesarean birth,
in this group of women (Doherty 2006). In addition, caesarean
births may not always be straightforward as complications of failed
epidural and spinal anaesthesia are more common in those who
are morbidly obese (Knight 2010).
Risks after birth for obese women
Complications after birth are more likely for obese women. An
increase in the incidence of postpartum haemorrhage and infections (including wound, urinary tract, perineum, chest and breast)
have been reported in obese women, when compared with normalweight women (Heslehurst 2008). Furthermore, excessive weight
gained during pregnancy in women who are already obese is likely
to be retained after the birth Rooney 2005, and may lead to health
complications such as diabetes and heart disease in later life (Linne
2003).
Risks to the neonate when the mother is obese
The neonates of obese women are at increased risk of increased
morbidity and mortality compared with babies born to normalweight women. Preterm birth is also more likely, and the time
to commence spontaneous respiration immediately after birth is
longer, more resuscitation is required, and there is more risk of
neonatal hypoglycaemia, in babies of obese women (Heslehurst
2008). Furthermore, the children of mothers who are obese at the
start of their pregnancy are likely to be overweight at the age of
three years (Olson 2009). A population-based case-control cohort
study of children aged between two and five years diagnosed with
autism spectrum disorder and developmental delays in California
2003 to 2010 indicates that maternal obesity in pregnancy may
be a risk factor for developmental delays in later life (Krakowiak
2012). Heavier women (those morbidly obese) are also more likely
to have increased risks of poor outcomes for the infant across the
childbearing continuum (Knight 2010).
Weight management for obese women in pregnancy
There is little robust evidence about optimal weight management
in pregnancy for obese women. Pregnancy weight varies between
individual women (Carmichael 1997), is not linear (Dawes 1991),
and is related to variables such as maternal age, pre-pregnancy
body size, parity, smoking, ethnicity, hypertension, and diabetes
(Abrams 1995; Chu 2009).
Guidance on weight gain in pregnancy across all maternal weights
is contentious. Over the last 20 years, guidance for clinical staff
on weight management in pregnancy has been based on recommendations from the US Institute of Medicine (Medicine 1990).
These guidelines have been controversial as they were based on
research studies that lacked sufficient rigour to be scientifically
sound. These guidelines were based on population-based observational studies (Johnson 1995), and studies that did not account
for other confounding variables (Feig 1998). In 2009, the US Institute of Medicine Guidelines were revised, and the new guidance based on a wider review of maternal and fetal outcomes (fetal size, risk of unplanned caesarean birth, and excessive postpartum weight retention) (Rasmussen 2009a). Early guidance recommended that obese pregnant women should gain a minimum of 7
kg (Medicine 1990), but in 2009, it was recommended that obese
pregnant women should limit their weight gain to between 5.0 kg
and 9.1 kg (Rasmussen 2009b).
Weight loss in obese women in pregnancy
Several observational studies suggest that some obese pregnant
women gain minimal weight in pregnancy, and even lose weight.
A retrospective review of pregnancy outcomes in the US found
that 11% of obese women lost weight, or maintained their weight,
compared to 0.1% of normal-weight women (Edwards 1996).
Bianco 1998 reviewed the outcomes of pregnant women with a
BMI greater than 35 and found that 9% lost weight, or gained no
weight, compared to 0.2% of normal-weight women. Two more
recent studies show similar results. Data from 136,802 women
giving birth to singleton fetuses between 1996 and 2001 across
21 states in the US indicated that low weight gain (less than 0.12
kg/wk) was more common in those obese (8.3%, n = 1315) and
morbidly obese (19%, n = 1287), than those normal weight (1.9%,
n = 1780) (Dietz 2006). Rode 2007 analysed data from 2248
Danish women of all weights at 37 weeks of gestation and found
that 9.7% (n = 15) of obese women (n = 155) gained less than
1 kg at this stage of their pregnancy. Another study reviewing
gestational weight gain and the risk of adverse pregnancy outcomes
reported that 12 of 328 obese women in the total sample of 2011
women lost weight, compared to only one woman in each of the
normal weight (n = 1227) and overweight (n = 456) groups (Oken
2009), although these differences were not significant.
More recently, published studies exploring gestational weight gain
suggest that incidence of weight loss in pregnancy increases as
women’s weight increases; Bodnar 2010, Hinkle 2010, Beyerlein
2011 and Blomberg 2011 found that weight loss in pregnancy was
more likely in morbidly obese women.
It is important to note that some women deliberately lose weight in
3
pregnancy. Bish 2009 and Cohen 2009 both reported around 8%
of pregnant women of all weights attempting to lose weight using
strategies such as limiting calories and fat intake, and increasing
exercise. When their data were analysed according to BMI category, the proportions increased to almost 13% of obese women
attempting weight loss in pregnancy (Bish 2009; Cohen 2009).
Risks associated with weight loss in obese women
during pregnancy
The current evidence related to weight loss and obstetric and
neonatal outcomes in all pregnant women is limited.
Maternal dieting and restricting food intake in the first trimester
of pregnancy may be associated with increased risk of the fetus
developing a neural tube defect (Carmichael 2003). Prolonged periods of fasting (greater than 13 hours) and not eating are also
linked to preterm birth and increased maternal corticotropin-releasing hormone concentrations (Herrmann 2001). Furthermore,
extreme weight loss (greater than 15% of pre-pregnancy weight)
in pregnant women suffering from hyperemesis gravidarum is associated with hospitalisation and the need for parenteral nutrition
(Fejzo 2009). These women suffered symptoms including gallbladder and liver dysfunction, renal failure and retinal haemorrhage (Fejzo 2009).
Low maternal weight gain and weight loss in pregnancy have been
associated with restrictions in fetal growth. Important evidence
is available from Holland during the winter of 1944/1945, when
food was severely limited because of a harsh winter and an embargo on food transportation. Many pregnant women at the time
had food intakes of less than 1000 kcal/daily for a period of seven
months. Analysis of birth records from this period in the western Netherlands indicate that birthweight, crown-heel length, and
head circumference decreased after exposure to famine in the third
trimester (Stein 2004). An analysis of maternal weight in pregnancy from women based in Amsterdam who gave birth between
August 1944 and April 1946 enabled comparisons of birth parameters immediately before famine, during food restriction, and after
liberation. Maternal weight loss and weight gain below 0.5 kg/
week were associated with reduced birthweight, length and ponderal indices (Stein 1995).
Some studies associate maternal weight loss with risks of preterm
birth, small-for-gestational-age infants, and some neonatal complications. Edwards 1996 found that obese women who lost
weight, or gained nothing in pregnancy, were significantly more
likely to give birth to smaller infants with birthweight less than
3000 g and be small-for-gestational age compared with obese
women who gained pregnancy weight within 1990 guidelines
(Medicine 1990). Furthermore, a systematic review suggested that
restricting protein/energy intake in overweight pregnant women,
or women who were gaining weight excessively, may harm the fetus (Kramer 2003). Dewey 1994 proposed that low energy intakes
in pregnancy may result in ketosis that can affect the fetus.
Other studies indicate that weight loss or gaining no weight when
obese may be beneficial. Bianco 1998 found that the incidence
of low birthweight and small-for-gestational-age births were not
increased in women with BMI greater than 35 who either lost
weight, or gained nothing, during pregnancy.
Emerging evidence from retrospective cohort studies suggests that
weight loss in pregnancy for obese women may have substantial
benefits for both the mother and infant. Oken 2009 reviewed 2011
mother-child pairs in the US against five adverse outcomes related
to gestational weight gain: preterm birth, small-for-gestationalage infant, large-for-gestational-age infant, substantial maternal
postpartum weight retention, and child obesity at age of three
years. The results indicated that the lowest predicted prevalence
of all five adverse outcomes occurred with a weight loss of 0.19
kg/week for obese women, which equates to a total loss of 7.6
kg for obese women over all of the pregnancy (Oken 2009).
Beyerlein 2011 reviewed 709,575 births in Bavaria from 2000 to
2007 and stratified the data according to BMI category. Small
weight losses of up to 5 kg were associated with lower risks for
pre-eclampsia in obese class II women and non-elective caesarean
section in obese class 1 women (Beyerlein 2011). Less large-forgestational-age births were also reported for obese class I women,
but an increase in small-for-gestational-age births was also noted
with weight loss for this category of obesity (Beyerlein 2011).
For women obese class III, no increase in neonatal morbidity or
mortality was observed (Beyerlein 2011).
Blomberg 2011 followed up 46,595 obese women from the
Swedish Medical Birth Registry. The data were stratified according
to obesity classes I, II and III and compared with the latest Institute of Medicine Guidelines (Rasmussen 2009b). The Blomberg
2011 analysis indicates that all obese women who lose weight in
pregnancy appear to have less risk of caesarean birth and delivering large-for-gestational-age infants, and no significantly increased
risk of developing pre-eclampsia, and other complications associated with birth and for the infant normally associated with obesity
when compared with weight gains of 5.0 to 9.0 kg. The overall
incidence of large for gestational age infants was 13.2% in obese
women II and III who gained within the current recommendations for their weight (Rasmussen 2009b), and reduced to 8.8%
if weight was lost (Blomberg 2011).
For heavier women (BMI greater than 40), weight loss in pregnancy appears to be more advantageous. In an exploration of the
outcomes of 120,251 pregnant obese women who delivered fullterm live singleton infants where the risks of pre-eclampsia, caesarean birth, small-for-gestation infants and large-for-gestation infants were assessed, the results indicated that a weight loss of up to
9 lbs (4kgs) may have minimal risks for women with BMI greater
than 40 (Kiel 2007). The Hinkle 2010 review also indicates that
women with BMI greater than 40 who lose weight during pregnancy have better outcomes. The lowest absolute risk of developing
pre-eclampsia, caesarean birth, and infant size being either smallfor-gestational age or large-for-gestational age for these women
4
was after a weight loss of zero to 4.1 kg (Hinkle 2010).
Clinical management of pregnancy weight in obese
women
Ideally, women with BMI greater than 30 kg/m² should plan to
lose weight before conception according to the National Institute
of Health and Clinical Excellence (NICE) (NICE 2010). In the
UK, NICE 2010 recommends that pregnant women identified as
obese at initial antenatal appointments should be advised about
the potential risks of losing weight whilst pregnant, and provided
with information and support about appropriate diet and exercise. NICE 2010 guidance discourages dieting when pregnant and
obese.
Description of the intervention
There are many interventions that aim to facilitate weight loss in
the non-pregnant population. These interventions are often multicomponent, combining one or more techniques. Health professionals and/or personnel with a range of training and experience
deliver the interventions.
Interventions used to reduce weight in non-pregnant populations
are defined in this review to provide background information to
the types of interventions that potentially could be used in future
randomised controlled trials designed to reduce weight in obese
pregnant women, if sufficient evidence is provided in observational
studies to support the safety of interventions. Interventions in the
non-pregnant population may include lifestyle interventions that
use techniques such as ’information giving’ related to lifestyle, for
example, nutrition (calorie restriction and eating behaviour modification) and exercise behaviour modification such as increasing
walking (Blackburn 2010). The delivery of information is variable entailing use of written material, internet, telephone contact and/or mail-based, and group-based or individualised contact (Schroder 2010; Stuart 2005; Witham 2010). Psychological
interventions may also be used. These include techniques that
aim to facilitate behaviour change such as self-help, peer support,
counselling, cognitive behavioural therapy, problem-solving therapy, goal setting, motivational interview techniques, and therapist contact (Pollak 2010; Warziski 2009). Complementary therapies such as acupressure and meditation may also be incorporated
into relevant interventions (Elder 2010; Spadaro 2008). In nonpregnant populations pharmacological agents such as Metformin,
Sibutramine and Orlistat can be used to reduce weight (Cannon
2009; Warziski 2009), and bariatric procedures such as gastric bypass surgery and laparascopic adjustable banding (Richens 2010)
are also utilised in non-pregnant individuals.
There are currently no evidence-based guidelines for clinical staff
and women related to weight management when obese and pregnant. Recent recommendations from NICE in the UK state that
obese women should not diet and deliberately lose weight when
pregnant because of risk of harm to the unborn child (NICE
2010). Furthermore, a Cochrane review has indicated that there is
a paucity of evidence to recommend interventions aimed at controlling excessive weight gain in pregnancy (Muktabhant 2012).
However, the risks of obesity, to both the mother and infant, are
substantial when pregnant.
Some obese women lose weight when pregnant (Bianco 1998;
Bish 2009; Cohen 2009; Dietz 2006; Edwards 1996; Oken 2009),
and especially those who are heaviest (Hinkle 2010). There is
insufficient evidence of the known benefits of weight loss when
obese and pregnant, or the harm that may occur to the unborn
baby.
Deliberate attempts to lose weight are common among the nonpregnant reproductive-aged population (Bish 2005). It is possible
therefore that some women may be dieting to lose weight around
the time of conception, and for the weeks prior to pregnancy
being confirmed (Cohen 2009). Furthermore, for some women
pregnancy is an opportunity to evaluate their lifestyle, and many
adjust their diet to eat more healthily for the sake of the child
(Gross 2007). Eating healthier when obese may result in weight
loss. There is a possibility that some obese women may not disclose
their attempts at weight loss when pregnant because they are aware
that it is socially unacceptable (Cohen 2009).
As it is clearly apparent that some obese women deliberately try to
lose weight in pregnancy (Bish 2009; Cohen 2009), the maternal
and neonatal outcomes of weight loss in pregnancy when obese
need to be established.
If weight loss in obese pregnant women is beneficial, maternal
and infant outcomes may be improved. Postnatal weight retention
will be limited and this may lead to greater control over weight
management in this group in the future. This may improve health
outcomes of future pregnancies. If weight loss is beneficial to obese
pregnant women, the development of feasible and acceptable interventions designed to facilitate weight loss may result in decreased
costs to health services. Furthermore, interventions designed to
reduce weight in obese pregnant women should be investigated to
explore their effectiveness in achieving their aim.
If weight loss is harmful for the obese pregnant woman, the effects
should be identified so that appropriate information and advice
can be developed.
OBJECTIVES
Why it is important to do this review
To evaluate the effectiveness of interventions that reduce weight
in obese pregnant women.
5
METHODS
Criteria for considering studies for this review
Types of studies
We considered all published and unpublished randomised and
quasi-randomised controlled trials, comparing a weight loss intervention with routine care or more than one weight loss intervention. We considered cluster-randomised trials.
Neonatal outcomes
1. Birthweight less than 2500 g and less than the 10th centile
for gestational age and sex.
2. Birth weight greater than 4000 g or larger than the 90th
centile for gestational age and sex.
3. Preterm birth (birth less than 37 completed weeks of
pregnancy).
4. Apgar scores less than seven at five minutes.
5. Hypoglycaemia - as defined by trialists.
Long-term outcomes
1. Maternal weight postpartum.
2. Childhood weight.
Types of participants
Obese pregnant women with a BMI equal to, or greater than 30
(kg/²m).
Search methods for identification of studies
Types of interventions
Electronic searches
All interventions that aim to reduce weight in pregnant women
who are obese such as eating and exercise behaviour modification,
or counselling.
Interventions in any setting.
Studies where the intervention is introduced in pregnancy.
We intended to undertake the following comparisons:
• one intervention versus no intervention;
• one intervention versus another intervention.
We contacted the Trials Search Co-ordinator to search the
Cochrane Pregnancy and Childbirth Group’s Trials Register (31
July 2012).
The Cochrane Pregnancy and Childbirth Group’s Trials Register
is maintained by the Trials Search Co-ordinator and contains trials
identified from:
1. monthly searches of the Cochrane Central Register of
Controlled Trials (CENTRAL);
2. weekly searches of MEDLINE;
3. weekly searches of EMBASE;
4. handsearches of 30 journals and the proceedings of major
conferences;
5. weekly current awareness alerts for a further 44 journals
plus monthly BioMed Central email alerts.
Details of the search strategies for CENTRAL, MEDLINE and
EMBASE, the list of handsearched journals and conference proceedings, and the list of journals reviewed via the current awareness service can be found in the ‘Specialized Register’ section
within the editorial information about the Cochrane Pregnancy
and Childbirth Group.
Trials identified through the searching activities described above
are each assigned to a review topic (or topics). The Trials Search
Co-ordinator searches the register for each review using the topic
list rather than keywords.
Types of outcome measures
Primary outcomes
1. Serious maternal morbidity (admission to high dependency
care) and/or death.
2. Neonatal admission to neonatal intensive care.
3. Perinatal death (including stillbirth).
Secondary outcomes
Maternal outcomes
1. Gestational diabetes.
2. Fetal distress in pregnancy or labour.
3. Postpartum haemorrhage.
4. Caesarean birth.
5. Infection (including wound, urinary tract, perineum, chest
and breast).
6. Weight (loss/gain/no change).
Searching other resources
We did not apply any date restrictions.
We did not apply any language restrictions.
We included abstracts because data and details were limited.
We contacted the authors of studies to obtain further information,
where relevant.
6
We used our professional contacts to seek further trial data.
Data collection and analysis
Selection of studies
Three review authors (Christine Furber, Tina Lavender, and Linda
McGowan) independently assessed for inclusion each study that
was identified through the search strategy. We resolved any disagreement through discussion.
In this version of the review we did not identify any studies for
inclusion. In updates of the review if we do identify trials which
meet our inclusion criteria we will use the methods set out in
Appendix 1 to carry out data extraction, assess bias in included
studies and analyse findings.
RESULTS
Description of studies
See: Characteristics of excluded studies.
See Characteristics of excluded studies.
The search of the Cochrane Pregnancy and Childbirth Group’s
Trials Register retrieved 63 reports equating to 49 studies. We
applied the eligibility criteria to each study and all were excluded.
In some situations, we emailed the authors of the study to clarify
the overall aim of the study. None of the studies identified aimed
to reduce weight in obese pregnant women. See Excluded studies.
DISCUSSION
This review indicates that obesity in pregnancy is of international
concern; most of the studies retrieved from the searches were
from Europe, North America, the Nordics, and Australia and New
Zealand, and a few were conducted in Brazil and Egypt. However, no randomised controlled trials designed to reduce maternal
weight in pregnant obese women were found. The majority of the
excluded randomised controlled trials including obese pregnant
women that were reviewed had outcomes which aimed to manage maternal weight gain within the parameters of the Institute
of Medicine Guidance (Medicine 1990), or to reduce excessive
weight gain. Others were designed to improve dietary and exercise behaviours, reduce infant weight, explore pregnancy outcome,
and minimise the effects of diabetes. A range of interventions were
included in these studies including dietary, exercise, and comprehensive lifestyle interventions. Others included interventions that
incorporated practices in the delivery of maternity care including
regular maternal weighing in pregnancy, and continuity in the delivery of maternity care. Pharmacological agents were used in some
studies, but they were not used to reduce weight. Furthermore, two
studies that used pharmacological interventions did not include
obese women. Metformin is currently being used in two studies to
minimise adverse outcomes for obese pregnant women (Norman
2010; Shehata 2012), however, weight loss is not a planned outcome.
From retrospective cohort observational studies (Beyerlein 2011;
Blomberg 2011; Oken 2009) for example, it is clear that weight
loss when obese in pregnancy is not unusual, whether this is intentional or not. Weight loss when obese should be monitored
carefully as although emerging observational studies of existing
data indicate that there are some improvements in outcomes such
as incidence of pre-eclampsia, caesarian section and adverse outcomes at birth for the mother and infant, the increase in small-forgestational-age infants is of concern (Beyerlein 2011; Blomberg
2011).
Excluded studies
None of the studies retrieved aimed to reduce weight in obese
pregnant women so were not relevant to this review. In total, 38
of the 49 studies retrieved reported results of trials. Eight trials
were excluded as the participants were either not pregnant (two
studies), or not obese (six studies).
Summary of main results
We found no relevant randomised controlled trials that were eligible for this review.
AUTHORS’ CONCLUSIONS
Risk of bias in included studies
No studies met the eligibility criteria for inclusion.
Effects of interventions
No studies met the eligibility criteria for inclusion.
Implications for practice
It is interesting to note from observational cohort studies that
obese pregnant women may lose weight and have better outcomes
than those who gain weight within recommended guidance, especially those who are morbidly obese. However weight loss in morbidly obese pregnant women does not eliminate risks associated
7
with pregnancy (Hinkle 2010; Beyerlein 2011; Blomberg 2011).
These observational studies indicate that the impact of weight loss
when obese and pregnant are complex, and also variable across
obese categories. Although there may be lesser likelihood of preeclampsia, caesarean birth and a large for gestational age fetus at
term, the potential for increased risk of small-for-gestational age
infants indicates that weight loss when pregnant and obese is not
without risk. More robust evidence of the outcomes of weight
loss when pregnant and obese across obesity categories is required
so that we can confidently understand outcomes, especially those
that impact on the neonate.
As there is no evidence from randomised controlled trials of interventions during pregnancy that weight loss in obese pregnant
women is beneficial, recommendations advocating weight reduction in pregnancy when obese cannot be supported. We suggest
that until evidence is available, no practice recommendations can
be made.
til evidence is available, it may not be appropriate to conduct a
randomised controlled trial designed to promote weight loss in
obese women in pregnancy. Furthermore, it is unlikely that an
ethics committee would provide favourable opinion to any such
study based on current evidence.
More understanding is required of the weight trajectory of obese
women during pregnancy. Prospective observational cohort studies of obese women during pregnancy will provide more data that
explains weight changes for this group, and short and long term
outcomes. Further studies are required to explore the efficacy of the
latest guidance from the Institute of Medicine (Blomberg 2011;
Rasmussen 2009b), especially as this guidance has not stratified
recommendations for weight gain across all obese categories (Artal
2010). Qualitative research will provide more insights into the
weight management strategies utilised by obese women during
pregnancy, especially those who deliberately lose weight.
Implications for research
The absence of randomised controlled trials related to reducing
weight in obese pregnant women may be a reflection of the lack of
evidence from observational cohort studies of the safety of weight
loss in this group. There is no robust evidence that indicates the
benefits, or harm, of losing weight when obese and pregnant. Un-
ACKNOWLEDGEMENTS
As part of the pre-publication editorial process, this review has
been commented on by four peers (an editor and three referees
who are external to the editorial team) and the Group’s Statistical
Adviser.
REFERENCES
References to studies excluded from this review
Althuizen 2006 {published data only}
Althuizen A, van Poppel MNM, Seidell JC, van der Wijden
C, van Mechelen W. Design of the New Life(style) study:
a randomised controlled trial to optimise maternal weight
development during pregnancy. BMC Public Health 2006;
6:168.
Angel 2011 {published data only}
Angel MD, De Haene J, Perez M, Hernandez G, Castaneda
D, King JC. Dietary patterns associated with gestational
weight gain and fat mass gain in overweight and obese
pregnant women. FASEB Journal 2011;25:783.15.
Asbee 2009 {published data only}
∗
Asbee SM, Jenkins TR, Butler JR, White J, Elliot M,
Rutledge A. Preventing excessive weight gain during
pregnancy through dietary and lifestyle counseling: a
randomized controlled trial. Obstetrics & Gynecology 2009;
113(2 Pt 1):305–12.
Asbee SM, Jenkins TR, Butler JR, White J, Elliott M,
Rutledge A. Dietary counselling prevents excessive weight
gain during pregnancy A randomized controlled trial.
Obstetrics & Gynecology 2008;111(4 Suppl):6S.
Badrawi 1993 {published data only}
∗
Badrawi H, Hassanein MK, Badraoui MHH, Wafa YA,
Shawky HA, Badrawi N. Pregnancy outcome in obese
pregnant mothers. New Egyptian Journal of Medicine 1993;
8(6):1717–26.
Badrawi H, Hassanein MK, Badraoui MHH, Wafa YA,
Shawky HA, Badrawi N. Pregnancy outcome in obese
pregnant women. Journal of Perinatal Medicine 1992;20
(Suppl. 1):203.
Boileau 1968 {published data only}
Boileau PA. Control of weight -gain during pregnancy:
Use of diethylpropion hydrochloride. Applied Therapeutics
1968;10:763–5.
Brand-Miller 2011 {published data only}
Brand-Miller J. A randomized, two-arm parallel dietary
intervention study to compare the effects of consuming a
low glycemic diet or wholegrain high fibre diet on infant
birth weight and body composition, complications related
to Gestational Diabetes Mellitus (GDM) and progression to
GDM diagnosis in women at high-risk of GDM. Australian
New Zealand Clinical Trials Register (www.anzctr.org.au)
2011; Vol. (accessed 11 February 2011).
Brownfoot 2011 {published data only}
Brownfoot F. In antenatal women, does weighing at each
8
visit compared with routine antenatal care reduce the
incidence of excessive weight gain during pregnancy?.
http://www.anzctr.org.au/ACTRN12610000331033.aspx
(accessed 27 July 2011).
Callaway 2010 {published data only}
Byrne NM, Groves AM, McIntyre HD, Callaway LK.
Changes in resting and walking energy expenditure and
walking speed during pregnancy in obese women. American
Journal of Clinical Nutrition 2011;94(3):819–30.
Callaway L. A randomized controlled trial using exercise to
reduce gestational diabetes and other adverse maternal and
neonatal outcomes in obese pregnant women - the pilot
study. Australian Clinical Trials Registry (www.actr.org.au)
(accessed 21 June 2007).
Callaway L, McIntyre D, Colditz P, Byrne N, Foxcroft
K, O’Connor B. Exercise in obese pregnant women: a
randomized study to assess feasibility. Hypertension in
Pregnancy 2008;27(4):549.
∗
Callaway LK, Colditz PB, Byrne NM, Lingwood BE,
Rowlands IJ, Foxcroft K, et al.Prevention of gestational
diabetes. Feasibility issues for an exercise intervention in
obese pregnant women. Diabetes Care 2010;33(7):1457–9.
Foxcroft KF, Rowlands IJ, Byrne NM, McIntyre HD,
Callaway LK, BAMBINO group. Exercise in obese pregnant
women: the role of social factors, lifestyle and pregnancy
symptoms. BMC Pregnancy and Childbirth 2011;11:4.
Chasen-Taber 2011 {published data only}
∗
Chasen-Taber L, Marcus BH, Stanek E, Ciccolo JT,
Marquez DX, Solomon MD, et al.A randomized controlled
trial of prenatal physical activity to prevent gestational
diabetes: design and methods. Journal of Women’s Health
2009;18(6):851–9.
Chasen-Taber L, Silveira M, Marcus BH, Braun B, Stanek
E. Markenson G. Feasibility and efficacy of a physical
intervention among pregnant women: The behaviors
affecting Baby and You (B.A.B.Y.) study. Journal of Physical
Activity and Health 2011;8(Suppl 2):S228–S238.
Dodd 2011 {published data only}
Dodd J. Limiting weight gain in overweight and obese
women during pregnancy to improve health outcomes:
a randomised trial. Australian Clinical Trials Registry
(www.actr.org.au) (accessed 21 June 2007).
∗
Dodd J, Turnbull DA, McPhee AJ, Wittert G, Crowther
CA, Robinson JS. Limiting weight gain in overweight
and obese women during pregnancy to improve health
outcomes: the LIMIT randomised controlled trial. BMC
Pregnancy and Childbirth 2011;11:79.
Faucher 2008 {published data only}
Faucher MA. Promotoras de salud and portion control:
a community intervention aimed at weight loss in lowincome Mexican-American women. Journal of Midwifery
and Women’s Health 2008;53(5):482.
Guelinckx 2010 {published data only}
Guelinckx I, Devlieger R, Mullie P, Vansant G. Effect of
lifestyle intervention on dietary habits, physical activity,
and gestational weight gain in obese pregnant women: a
randomized controlled trial. American Journal of Clinical
Nutrition 2010;91(2):373–80.
Haakstad 2011 {published data only}
Haakstad LAH, Bo K. Effect of regular exercise on
prevention of excessive weight gain in pregnancy:
a randomised controlled trial. European Journal of
Contraception and Reproductive Health Care 2011;16(2):
116–25.
Harrison 2011 {published data only}
Harrison CL, Lombard CB, Gibson-Helm M, Deeks
A, Teede HJ. Limiting excess weight gain in high-risk
pregnancies: A randomized controlled trial. Endocrine
Reviews 2011;32(3 Meeting Abstracts):P1–466.
Huang 2011 {published data only}
Huang TT, Yeh CY, Tsai YC. A diet and physical activity
intervention for preventing weight retention among
Taiwanese childbearing women: a randomised controlled
trial. Midwifery 2011;27(2):257–64.
Hui 2012 {published data only}
Hui A, Back L, Ludwig S, Gardiner P, Sevenhuysen G, Dean
H, et al.Lifestyle intervention on diet and exercise reduced
excessive gestational weight gain in pregnant women under
a randomised controlled trial. BJOG: an international
journal of obstetrics and gynaecology 2012;119(1):70–7.
Jackson 2011 {published data only}
Jackson RA, Stotland NE, Caughey AB, Gerbert B.
Improving diet and exercise in pregnancy with Video
Doctor counseling: a randomized trial. Patient Education
and Counseling 2011;83(2):203–9.
Jeffries 2009 {published data only}
Jeffries K, Shub A, Walker SP, Hiscock R, Permezel M.
Reducing excessive weight gain in pregnancy: a randomised
controlled trial. Medical Journal of Australia 2009;191(8):
429–33.
Koushkie 2003 {published data only}
Koushkie M, Nikbakht H, Parsanezhad ME, Jahromi
BN, Salami F, Khoshnam E. Aerobic exercise during third
trimester of pregnancy, and pregnancy symptoms and
outcomes. Canadian Journal of Applied Physiology 2003;28
Suppl:S73.
Krummel 2009 {published data only}
Krummel DA. DHA supplements to improve insulin
sensitivity in obese pregnant women (the omega-3
pregnancy study). http://clinicaltrials.gov/ct2/show/
NCT00865683 (accessed 31 July 2009).
Lavender 2011 {published data only}
Lavender T. A pilot randomised controlled trial to evaluate
the impact of attending The Lifestyle Course (TLC) on the
health of pregnant women with a Body Mass Index (BMI) of
30kg/m2 or more and their babies. http://www.controlledtrials.com/isrctn/pf/09432573 (accessed 4 July 2011).
Lombard 2011 {published data only}
Lombard C, Harrison C, Teede H. A randomized controlled
trial investigating self-weighing and the prevention of excess
9
weight gain in early pregnancy. Endocrine Reviews 2011;32
(3 Meeting Abstracts):P2–768.
www.eme.ac.uk/projectfiles/0824609protocol.pdf (accessed
12.10.2011).
Louie 2011 {published data only}
Louie JCY, Markovic TP, Perera N, Foote D, Petocz P, Ross
GP, et al.A randomized controlled trial investigating the
effects of a low-glycemic index diet on pregnancy outcomes
in gestational diabetes mellitus. Diabetes Care 2011;34(11):
2341–6.
Ong 2009 {published data only}
Ong MJ, Guelfi KJ, Hunter T, Wallman KE, Fournier
PA, Newnham JP. Supervised home-based exercise may
attenuate the decline of glucose tolerance in obese pregnant
women. Diabetes & Metabolism 2009;35(5):418–21.
Luoto 2011 {published data only}
Luoto R, Kinnunen TI, Aittasalo M, Kolu P, Raitanen J,
Ojala K, et al.Primary prevention of gestational diabetes
mellitus and large-for-gestational-age newborns by lifestyle
counseling: a cluster-randomized controlled trial. PLoS
Medicine 2011;8(5):1–11.
Magee 1990 {published data only}
Magee MS, Knopp RH, Benedetti TJ. Metabolic effects of
1200-kcal diet in obese pregnant women with gestational
diabetes. Diabetes 1990;39:234–40.
Moholdt 2011 {published data only}
Moholdt TT, Salvesen K, Ingul CB, Vik T, Oken E,
Morkved S. Exercise Training in Pregnancy for obese
women (ETIP): study protocol for a randomised controlled
trial. Trials 2011;12:154.
Moses 2006 {published data only}
Moses RG, Luebcke M, Davis WS, Coleman KJ, Tapsell
LC, Petocz P, et al.Effect of a low-glycemic-index diet
during pregnancy on obstetric outcomes. American Journal
of Clinical Nutrition 2006;84:807–12.
Moses 2009 {published data only}
Moses RG, Barker M, Winter M, Petocz P, Brand-Miller J.
Can a low - glycemic index diet reduce the need for insulin
in gestational diabetes mellitus? A randomized controlled
trial. Diabetes Care 2009;32(6):996–1000.
Nagle 2011 {published data only}
Nagle C, Skouteris H, Hotchin A, Bruce L, Patterson D,
Teale G. Continuity of midwifery care and gestational
weight gain in obese women: a randomised controlled trial.
BMC Public Health 2011;11:174.
Nascimento 2011 {published data only}
Nascimento SL, Surita FG, Parpinelli MA, Siani S, Pinto
e Silva JL. The effect of an antenatal physical exercise
programme on maternal/perinatal outcomes and quality of
life in overweight and obese pregnant women: a randomised
clinical trial. BJOG: an international journal of obstetrics and
gynaecology 2011;118(12):1455–63.
Norman 2010 {published data only}
∗
Norman J. A multicentre randomised placebo controlled
clinical trial of metformin versus placebo in pregnant
women to reduce the risk of obesity and metabolic
syndrome in their babies. http://www.controlled-trials.com/
ISRCTN51279843/EMPOWaR (accessed 2012).
Weeks A. Does metformin reduce excess birthweight
in offspring of obese pregnant women? A randomised
controlled trial of efficacy, exploration of mechanisms
and evaluation of other pregnancy complications. http://
Parat 2009 {published data only}
Parat S. Impact of education during pregnancy in overweight
pregnant women (ETOIG). http://clinicaltrials.gov/ct2/
show/NCT00804765 (accessed 4 January 2009).
Phelan 2011 {published data only}
Phelan S, Phipps MG, Abrams B, Darroch F, Schaffner A,
Wing RR. Factors associated with success in the “fit for
delivery” intervention to reduce excessive gestational weight
gain. Obesity 2011;19(Suppl 1):S95.
∗
Phelan S, Phipps MG, Abrams B, Darroch F, Schaffner
A, Wing RR. Randomized trial of a behavioral intervention
to prevent excessive gestational weight gain: the Fit for
Delivery Study. American Journal of Clinical Nutrition
2011;93(4):772–9.
Polley 2002 {published data only}
Polley BA, Wing RR, Sims CJ. Randomized controlled
trial to prevent excessive weight gain in pregnant women.
International Journal of Obesity & Related Metabolic
Disorders: Journal of the International Association for the
Study of Obesity 2002;26(11):1494–502.
Poston 2009 {published data only}
∗
Poston L. Improving pregnancy outcome in obese women:
a feasibility study. http://www.controlled-trials.com/
ISRCTN89971375 (accessed 22 June 2012).
Poston L, Holmes B, Kinnunen T, Croker H, Bell R,
Sanders T, et al.A complex intervention to improve outcome
in obese pregnancies; the upbeat study. Archives of Disease
in Childhood: Fetal and Neonatal Edition 2011;96(Suppl 1):
Fa97.
Quinlivan 2011 {published data only}
Quinlivan J. A randomised trial of a multidisciplinary
teamcare approach involving obstetric, dietary and clinical
psychological input in obese pregnant women to reduce the
incidence of gestational diabetes. Australian Clinical Trials
Register (www.actr.org.au) (accessed 6 December 2005).
∗
Quinlivan JA, Lam LT, Fisher J. A randomised trial of a
four-step multidisciplinary approach to the antenatal care
of obese pregnant women. Australian and New Zealand
Journal of Obstetrics and Gynaecology 2011;51(2):141–6.
Rae 2000 {published data only}
Rae A, Bond D, Evans S, North F, Roberman B, Walters B.
A randomised controlled trial of dietary energy restriction
in the management of obese women with gestational
diabetes. Australian & New Zealand Journal of Obstetrics &
Gynaecology 2000;40(4):416–22.
10
Rhodes 2010 {published data only}
Pawlak DB. Glycemic load and infant birth weight in
pregnant overweight/obese women. http://clinicaltrials.gov/
ct2/show/NCT00364403 (accessed 21 June 2007) 2007.
∗
Rhodes ET, Pawlak DB, Takoudes TC, Ebbeling CB,
Feldman HA, Lovesky MM, et al.Effects of a low-glycemic
load diet in overweight and obese pregnant women: a pilot
randomized controlled trial. American Journal of Clinical
Nutrition 2010;92(6):1306–15.
Santos 2005 {published data only}
Santos IA, Stein R, Fuchs SC, Duncan BB, Ribeiro JP,
Kroeff LR, et al.Aerobic exercise and submaximal functional
capacity in overweight pregnant women: a randomized
trial. Obstetrics & Gynecology 2005;106(2):243–9.
Shehata 2012 {published data only}
∗
Shehata H. Metformin in obese non-diabetic pregnant
women (MOP). http://clinicaltrilas.gov/ct2/show/
NCT01273584 [Accessed 17th September 2012] 2012.
Silverman 1971 {published data only}
Silverman M, Okun R. The use of an appetite suppressant
(diethylpropion hydrochloride) during pregnancy. Current
Therapeutic Research, Clinical and Experimental 1971;13:
648–53.
360 obese pregnant women. Diabetes Care 2011;34(12):
2502–7.
Vitolo 2011 {published data only}
Vitolo MR, Fraga Bueno MS, Mendes Gama C. Impact of
a dietary counseling program on the gain weight speed of
pregnant women attended in a primary care service. Revista
Brasileira de Ginecologia e Obstetricia 2011;33(1):13–9.
Wolff 2008 {published data only}
Wolff S, Legarth J, Vangsgaard K, Toubro S, Astrup A.
A randomized controlled trial of the effects of dietary
counseling on gestational weight gain and glucose
metabolism in obese pregnant women. International Journal
of Obesity 2008;32:495–501.
Additional references
Abrams 1995
Abrams B, Selvi, S. Maternal weight gain pattern and birth
weight. Obstetrics & Gynecology 1995;86:163–9.
Artal 2010
Artal R, Lockwood CJ, Brown HL. Weight gain
recommendations in pregnancy and the obesity epidemic.
Obstetrics & Gynecology 2010;115:152–5.
Szmeja 2011 {published data only}
Szmeja MA, Grivell RM, Deussen AR, Dodd JM.
Evaluation of information provision to women who are
overweight or obese during pregnancy. Journal of Paediatrics
and Child Health 2011;47(Suppl 1):78.
Baeton 2001
Baeten JM, Bukusi EA, Lambe M. Pregnancy complications
and outcomes among overweight and obese nulliparous
women. American Journal of Public Health 2001;91(3):
436–40.
Teede 2011 {published data only}
Teede HJ, Harrison CL, Gibson-Helm M, Lombard CB.
Improving physical activity in high-risk pregnancies: a
randomized controlled trial. Endocrine Reviews 2011;32(3
Meeting Abstracts):P1–467.
Beyerlein 2011
Beyerlein A, Schiessl B, Lack N, von Kries R. Associations
of gestational weight loss with birth-related outcome: a
retrospective cohort study. BJOG: an international journal
of obstetrics and gynaecology 2011;118:55–61.
Te Morenga 2010 {published data only}
Te Morenga L, Williams S, Brown R, Mann J. Effect of a
relatively high-protein, high fiber diet on body composition
and metabolic risk factors in overweight women. European
Journal of Clinical Nutrition 2010;64:1323–1.
Thornton 2009 {published data only}
Thornton YS, Smarkola C, Kopacz SM, Ishoof SB. Perinatal
outcomes in nutritionally monitored obese pregnant
women: a randomized clinical trial. Journal of the National
Medical Association 2009;101:569–77.
Vinter 2011 {published data only}
Vinter C. Lifestyle and pregnancy: the clinical effect of
lifestyle intervention during pregnancy in obese women
(LiP). ClinicalTrials.gov (http:clinicaltrials.gov) (accessed
September 2011).
Vinter C, Jensen D, Ovesen P, Beck-Nielsen H, Lamont R,
Jorgensen J. Postpartum weight retention and breastfeeding
among obese women from the LiP (Lifestyle in Pregnancy)
Study. Acta Obstetricia et Gynecologica Scandinavica 2012;
91(Suppl 159):141–2.
∗
Vinter CA, Jensen DM, Ovesen P, Beck-Nielsen H,
Jorgensen JS. The LiP (Lifestyle in Pregnancy) study: a
randomized controlled trial of lifestyle intervention in
Bianco 1998
Bianco AT, Smilen SW, Davis Y, Lopez S, Lapinski R,
Lockwood CJ. Pregnancy outcome and weight gain
recommendations for the morbidly obese woman. Obstetrics
& Gynecology 1998;91:97–102.
Bish 2005
Bish CL, Blanck HM, Serdula MK, Marcus M, Kohl HW
3rd, Khan LK. Diet and physical activity behaviors among
Americans trying to lose weight: 2000 Behavioral Risk
Factor Surveillance System. Obesity Research 2005;13(3):
596–607.
Bish 2009
Bish CL, Chu SY, Shapiro-Mendoza CK, Sharma AJ,
Blanck HM. Trying to lose or maintain weight during
pregnancy - United States, 2003. Maternal Child Health
Journal 2009;13:286–92.
Blackburn 2010
Blackburn GL, Wollner S, Heynsfield SB. Lifestyle
interventions for the treatment of class III obesity: a primary
target for nutrition medicine in the obesity epidemic.
American Journal of Clinical Nutrition 2010;91 Suppl:
289S–292S.
11
Blomberg 2011
Blomberg M. Maternal and neonatal outcomes among
obese women with weight gain below the new Institute of
Medicine recommendations. Obstetrics & Gynecology 2011;
117(5):1065–0.
Bodnar 2010
Bodnar LM, Siega-Riz AM, Simhan N, Himes KP, Abrams
B. Severe obesity, gestational weight gain, and adverse birth
outcomes. American Journal of Clinical Nutrition 2010;91:
1642–8.
Cannon 2009
Cannon CP, Kumar A. Treatment of overweight and obesity:
lifestyle, pharmacologic, and surgical options. Clinical
Cornerstone 2009;9(4):55–71.
Carmichael 1997
Carmichael S, Abrams B, Selvin S. The pattern of maternal
weight gain in women with good pregnancy outcomes.
American Journal of Public Health 1997;87(12):1984–8.
Carmichael 2003
Carmichael SL, Shaw GM, Schaffer DM, Laurent C,
Selvin S. Dieting behaviors and risk of neural tube defects.
American Journal of Epidemiology 2003;158:1127–31.
Chu 2007
Chu SY, Kim SY, Lau J, Schmid HY, Dietz PM, Callaghan
WM, et al.Maternal obesity and risk of stillbirth: a meta
analysis. American Journal of Obstetrics & Gynecology 2007;
197(3):223–8.
Chu 2009
Chu SY, Callaghan WM, Bish CL, D’Angelo D. Gestational
weight gain by body mass index among US women
delivering live births, 2004-2005: fuelling future obesity.
American Journal of Obstetrics and Gynecology 2009;200(3):
271.e1–7.
Cohen 2009
Cohen JH, Kim H. Sociodemographic and health
characteristics associated with attempting weight loss during
pregnancy. Preventing Chronic Disease 2009;6(1):A07.
Dawes 1991
Dawes MG, Grudzinskas JG. Patterns of maternal weight
gain in pregnancy. British Journal of Obstetrics and
Gynaecology 1991;98:195–201.
Dewey 1994
Dewey KG, McCrory MA. Effects of dieting and physical
activity on pregnancy and lactation. American Journal of
Clinical Nutrition 1994;59 Suppl:446S–535S.
Doherty 2008
Doherty L, Norwitz ER. Prolonged pregnancy: when
should we intervene?. Current Opinion in Obstetrics and
Gynecology 2008;20(6):519–27.
Edwards 1996
Edwards LE, Hellerstedt WL, Alton IR, Story M, Himes
JH. Pregnancy complications and birth outcomes in obese
and normal-weight women: effects of gestational weight
change. Obstetrics & Gynecology 1996;87:389–94.
Egger 1997
Egger M, Davey Smith G, Schneider M, Minder C. Bias
in meta-analysis detected by a simple, graphical test. BMJ
1997;315(7109):629–34.
Elder 2010
Elder C, Gallison C, Lindberg NM, DeBar L, Funk K,
Ritenbaugh C, et al.Randomized trial of Tapas Acupressure
Technique for weight loss maintenance: rationale and study
design. Journal of Alternative & Complementary Medicine
2010;16(6):683–90.
Feig 1998
Feig DS, Naylor CD. Eating for two: are guidelines for
weight gain during pregnancy too liberal?. Lancet 1998;
351:1054–5.
Fejzo 2009
Fejzo MS, Poursharif B, Korst LM, Munch S, MacGibbon
KW, Romero R, et al.Symptoms and pregnancy outcomes
associated with extreme weight loss among women with
hyperemesis gravidarum. Journal of Women’s Health 2009;
18(12):1981–7.
Flenady 2011
Flenady V, Koopmans L, Middleton P, Froen JF, Smith GC,
Gibbons K, et al.Major risk factors for stillbirth in highincome countries: a systematic review and meta-analysis.
Lancet 2011;377:1331–40.
Gross 2007
Gross H, Pattison H. Sanctioning Pregnancy. A Psychological
Perspective on the Paradoxes and Culture of Research. London
and New York: Routledge, 2007.
Harbord 2006
Harbord RM, Egger M, Sterne JA. A modified test for
small-study effects in meta-analyses of controlled trials
with binary endpoints. Statistics in Medicine 2006;25(20):
3443–57.
Dietz 2006
Dietz PM, Callaghan WM, Cogswell ME, Morrow B, Ferre
C, Schieve LA. Combined effects of prepregnancy body
mass index and weight gain during pregnancy on the risk of
preterm delivery. Epidemiology 2006;17(2):170–7.
Herrmann 2001
Herrmann TS, Siega-Riz AM, Hobel CJ, Aurora C, DunkelSchetter C. Prolonged periods without food intake during
pregnancy increase risk for elevated maternal corticotropinreleasing hormone concentrations. American Journal of
Obstetrics and Gynecology 2001;185(2):403–12.
Doherty 2006
Doherty DA, Magann EF, Franxis J, Morrison JC,
Newnham JP. Pre-pregnancy body mass index and
pregnancy outcomes. International Journal of Gynecology &
Obstetrics 2006;95:242–7.
Heslehurst 2008
Heslehurst N, Simpson L, Ells J, Rankin J, Wilkinson J,
Lang R, et al.The impact of maternal BMI on pregnancy
outcomes with immediate short-term obstetric resource
implications: a meta-analysis. Obesity 2008;9:635–83.
12
Higgins 2011
Higgins JPT, Green S, editors. Cochrane Handbook for
Systematic Reviews of Interventions Version 5.1.0 [updated
March 2011]. The Cochrane Collaboration, 2011.
Available from www.cochrane-handbook.org.
Hinkle 2010
Hinkle SN, Sharma AJ, Dietz PM. Gestational weight
gain in obese mothers and associations with fetal growth.
American Journal of Clinical Nutrition 2010;92:644–51.
Johnson 1995
Johnson JW, Yancey MK. A critique of the new
recommendations for weight gain in pregnancy. American
Journal of Obstetrics and Gynecology 1995;174:254–8.
Kerrigan 2009
Kerrigan AM, Kingdon C. Maternal obesity and pregnancy:
a retrospective study. Midwifery 2010;26(1):138–46.
Kiel 2007
Kiel DW, Dodson EA, Artal R, Boehner TK, Leet TL.
Gestational weight gain and pregnancy outcomes in obese
women. Obstetrics & Gynecology 2007;110(4):752–8.
Knight 2010
Knight M, Kurinczuk JJ, Spark P, Brocklehurst P, on
behalf of the UK Obstetric Surveillance System. Extreme
obesity in pregnancy in the United Kingdom. Obstetrics &
Gynecology 2010;115(5):989-97.
NICE 2010
National Institute for Health and Clinical Excellence.
Weight Management Before, During and After Pregnancy.
London: NICE, 2010.
Oken 2009
Oken E, Kelinman KP, Belfort MB, Hammitt JK, Gillman
MW. Associations of gestational weight gain with short and
longer-term maternal and child health outcomes. American
Journal of Epidemiology 2009;170(2):173–80.
Oleson 2006
Oleson AW, Westergaard JG, Olsen J. Prenatal risk
indicators of a prolonged pregnancy: the Danish Birth
Cohort 1998-2001. Acta Obstetricia et Gynecologica
Scandinavica 2006;85(11):1338–41.
Olson 2009
Olson CM, Strawderman MS, Dennison BA. Maternal
weight gain during pregnancy and child weight at age 3
years. Maternal and Child Health Journal 2009;13:839–46.
Ovesen 2011
Oveson P, Tasmussen S, Kesmodel U. Effect of prepregnancy
maternal overweight and obesity on pregnancy outcome.
Obstetrics & Gynecology 2011;118:305–12.
Pollak 2010
Pollack KI, Alexander SC, Coffman CJ, Tulsky JA, Lyna P,
Dolor RJ, et al.Physician communication techniques and
weight loss in adults Project CHAT. American Journal of
Preventive Medicine 2010;39(4):321–8.
Krakowiak 2012
Krakowiak P, Walker CK, Bremer AA, Baker AS, Ozooff
S, Hansen RL, et al.Maternal metabolic conditions and
risk for autism and other neurodevelopmental disorders.
Pediatrics 2012;129(5):e1121–8.
Rankin 2010
Rankin J, Tennant PWG, Stothard KJ, Bythell M,
Summerbell CD, Bell R. Maternal body mass index and
congenital anomaly risk: a cohort study. International
Journal of Obesity 2010;34:1371–80.
Kramer 2003
Kramer MS, Kakuma R. Energy and protein intake in
pregnancy. Cochrane Database of Systematic Reviews 2003,
Issue Issue 4. [DOI: 10.1002/14651858.CD000032]
Rasmussen 2009a
Rasmussen KM Catalano PM, Yaktine AL. New guidelines
for weight gain during pregnancy: what obstetricians/
gynaecologists should know. Current Opinion in Obstetrics
and Gynecology 2009;21:521–6.
Linne 2003
Linne Y, Dye L, Barkelin B, Rossner S. Weight development
over time in parous women: The SPAWN study: 15
years follow-up. International Journal of Obesity 2003;27:
1516–22.
Medicine 1990
Institute of Medicine. Nutrition During Pregnancy.
Washington DC: National Academy Press, 1990.
Metwally 2008
Metwally M, Ong KJ, Ledger WL, Chiu T. Does high body
mass index increase the risk of miscarriage after spontaneous
and assisted conception? A meta-analysis of th evidence.
Fertility and Sterility 2008;90(3):714–26.
Muktabhant 2012
Muktabhant B, Lumbiganon P, Ngamjarus C, Dowswell T.
Interventions for preventing excessive weight gain during
pregnancy. Cochrane Database of Systematic Reviews 2012,
Issue 4. [DOI: 10.1002/14651858.CD007145.pub2]
Rasmussen 2009b
Rasmussen KM, Yaktine AL, eds. Weight Gain During
Pregnancy: Reexamining the Guidelines. Washington DC:
The National Academies Press, 2009.
RevMan 2011
The Nordic Cochrane Centre, The Cochrane Collaboration.
Review Manager (RevMan). 5.1. Copenhagen: The Nordic
Cochrane Centre, The Cochrane Collaboration, 2011.
Richens 2010
Richens Y, Fiennes A. Bariatric surgery and care of pregnant
women. In: Richens Y, Lavender T editor(s). Care for
Pregnant Women Who Are Obese. London: Quay Books,
2010:19–27.
Rode 2007
Rode L, Heggard HK, Kjaergaard H, Moller LF, Tabor
A, Ottesen B. Association between maternal weight gain
and birth weight. Obstetrics & Gynecology 2007;109(6):
1309–15.
13
Rooney 2005
Rooney BL, Schauberger CW, Mathiason MA. Impact of
perinatal weight change on long-term obesity and obesityrelated illnesses. Obstetrics & Gynecology 2005;106(6):
1349–56.
Schroder 2010
Schroder KEE. Computer-assisted dieting: effects of a
randomised controlled intervention. Psychology and Health
2010;25:519–34.
Sebire 2001
Sebire N, Jolly M, Harris J, Wadsworth J, Joffe M, Beard
R, et al.Maternal obesity and pregnancy outcome: a study
of 287,213 pregnancies In London. International Journal
of Obesity and Related Metabolic Disorders 2001;25(8):
1175–82.
Spadaro 2008
Spadaro KC. Weight Loss: Exploring Self-regulation Through
Mindfulness Meditation [PhD dissertation]. Pittsburgh:
University of Pittsburgh, 2008.
Stein 1995
Stein AD, Ravelli ACJ, Lumey LH. Famine, third-trimester
pregnancy weight gain, and intrauterine growth: the Dutch
famine birth cohort study. Human Biology 1995;67(1):
135–49.
Stein 2004
Stein AD, Zybert PA, Van der Bor M, Lumer LH.
Intrauterine famine exposure and body proportions at
birth: the Dutch hunger winter. International Journal of
Epidemiology 2004;33:831–6.
Stothard 2009
Stothard KJ, Tennat PWG, Bell R, Rankin, J. Maternal
overweight and obesity and the risk of congenital anomalies.
JAMA 2009;3016:636–50.
Stuart 2005
Stuart WP, Broome ME, Smith BA, Weaver M. An
integrative review of interventions for adolescent weight
loss. Journal of School Nursing 2005;21(2):77–85.
Warziski 2009
Warziki M, Yang K, Hravnak M, Sereika SM, Ewing
LJ, Burke LE. Randomized clinical trials of weight loss
maintenance. Journal of Cardiovascular Nursing 2009;24(1):
58–80.
Witham 2010
Witham MD, Avenell A. Interventions to achieve long-term
weight loss in obese older people. A systematic review and
meta-analysis. Age and Ageing 2010;39:176–84.
World Health Organization 2000
World Health Organization. . Obesity: Preventing and
Managing the Global Epidemic. Geneva: WHO, 2000.
World Health Organization 2006
World Health Organization. Overweight and Obesity. Fact
sheet N°311. Geneva: WHO, 2006.
Zaninotto 2006
Zaninotto P, Wardle H, Samakakis E, Mindell J, Head
J. Forecasting Obesity to 2010. London: Department of
Health, 2006.
Zhang 2007
Zhang J, Bricker L, Wray S, Quenby S. Poor uterine
contractility in obese women. BJOG: an international
journal of obstetrics and gynaecology 2007;114:343–8.
∗
Indicates the major publication for the study
14
CHARACTERISTICS OF STUDIES
Characteristics of excluded studies [ordered by study ID]
Study
Reason for exclusion
Althuizen 2006
This paper is a protocol of a study in The Netherlands. The intervention (the New Life(style) intervention
program) is not aimed at reducing weight in obese women, but at helping pregnant women to gain weight
within IOM guidelines. The authors were emailed (March 2012) and they confirmed that the study is now
complete. The author confirmed that the study was not aimed at obese women although there were no weight
restrictions on recruitment. Of the 250 women in the sample, only 8 were obese
Angel 2011
This is a brief conference abstract of a randomised controlled trial in the US. The intervention did not aim to
reduce weight in obese pregnant women so has been excluded
Asbee 2009
Brief conference abstract of a randomised controlled trial in the US. This Intervention did not aim to reduce
weight in obese pregnant women but prevent excessive weight gain. It is also not clear whether the participants
were obese or not
Badrawi 1993
This Intervention did not aim to reduce weight in obese pregnant women but to investigate pregnancy outcome
when obese pregnant women were given either a 1500-2000 Kcal daily diet compared to a diet of no restriction.
The abstract reports that those on an unrestricted diet had a high rate of weight gain but there is no information
about the intervention group weight. The study is excluded as the intervention did not aim to reduce maternal
weight
Boileau 1968
This report of a randomised controlled trial in Canada included an intervention that did not aim to reduce
weight in obese pregnant women, but to evaluate the anorexic efficacy of Diethylproprion hydrochloride in
continuous release formulation. Some participants lost weight in the data. It is not clear if these women were
obese when they commenced the study as BMI was not reported. Maternal weight on entry to the study was
assessed using the author’s ’office standard’ of more than 2-3 pounds per month
Brand-Miller 2011
The intervention will not aim to reduce weight so is not applicable to this review. The intervention is a low
glycaemic diet compared with a whole grain diet. The aim of the study is to compare the effects of the two diets.
Accessed from the Australian New Zealand Clinical Trials Registry (ANZCTR) (ACTRN1261000001055).
Brownfoot 2011
The intervention is maternal weight measurement recordings during routine antenatal care compared with
antenatal care that does not include weighing. The aim is to evaluate whether weighing at each antenatal visit
reduces excessive weight gain in pregnancy. It is not clear if obese pregnant women will be directly targeted for the
study. As the intervention does not aim to reduce maternal weight in obese women in pregnancy, it is excluded.
Accessed from the Australian New Zealand Clinical Trials Registry (ANZCTR) (ACTRN12610000331033).
Callaway 2010
The intervention was a highly supported individualised exercise intervention versus usual activity. The intervention was not designed to reduce weight in obese pregnant women so is not relevant for this review. Although
the participants were reported as being obese, changes to weight or BMI are not reported in the study. The study
was a pilot to explore the feasibility of an individualised exercise programme to prevent gestational diabetes in
obese pregnant women
15
(Continued)
Chasen-Taber 2011
The intervention was a highly supported individualised exercise intervention versus provision of a booklet
about health and wellness in pregnancy. The intervention was not designed to reduce weight in obese pregnant
women so is not relevant for this review. Although the participants were reported as being obese, changes to
weight or BMI are not reported in the study. The study was a pilot to explore the feasibility of an individualised
exercise programme to prevent gestational diabetes in obese pregnant women. This study was completed in
the US
Dodd 2011
The intervention consists of comprehensive diet and lifestyle advice based on behavioural techniques delivered
by a dietician and trained researchers. Dietary advice will be based on current Australian guidelines. The control
group receive usual antenatal care. A power calculation indicates that 2180 women are required for the study.
The authors were emailed March 2012 who confirmed that the study is now complete and results will be
published in approximately 1 year. The study is excluded as the intervention does not aim to reduce weight in
obese pregnant women
Faucher 2008
This is a conference abstract. The abstract describes a pilot intervention in portion control that is aimed to
lead to weight loss in low-income women. It is not clear if the women were obese. It is clear that pregnant
women were not included in the study. The abstract is excluded as the participants were not pregnant
Guelinckx 2010
This is a randomised controlled trial including 195 obese pregnant women conducted in Belgium. Women
were randomised to 1 of 3 groups: nutritional advice from a brochure versus brochure and lifestyle advice from
a nutritionist versus usual care. Outcomes were dietary habits, physical activity, weight gain in pregnancy and
obstetric and neonatal outcomes. It is reported in the paper that gestational weight gain was not significantly
different between the groups, and did not decrease in the 2 intervention groups. The study is excluded as the
intervention did not aim to reduce weight in obese pregnant women
Haakstad 2011
This is a randomised controlled trial - assessor blinded carried out in Norway. The participants were sedentary,
nulliparous pregnant women - obese women were not directly targeted but 11 of the 105 participants were
obese. The intervention was an exercise group versus usual care. The outcomes were maternal weight gain and
proportion of women gaining above the IOM guidelines.The results indicate that there was no difference in
maternal weight gain between both groups. The study is excluded as the intervention did not aim to reduce
weight in obese pregnant women, but to prevent excessive weight gain
Harrison 2011
This was a brief conference abstract of a randomised controlled trial in Australia. The intervention was a low
intensity lifestyle designed to reduce excessive weight gain, not reduce weight, in overweight pregnant women.
The outcome was to assess the efficacy of the intervention, therefore the study has been excluded
Huang 2011
This is a randomised controlled trial in Taiwan. The participants were all pregnant women (n = 240), including
some who were obese.The intervention included individual counselling about diet and physical exercise over
2 time periods. 1 group through pregnancy till 6 months postpartum, and the other from birth till 6 months
postpartum. The aim of the study was to explore the effect of the interventions on weight retention. The results
indicate that the intervention is effective for reducing postpartum weight retention. However, the study did
not aim to reduce weight in obese pregnant women, so it has been excluded
Hui 2012
This is a randomised controlled trial in Canada. The intervention aimed to explore the effect of an exercise and
dietary intervention on excessive gestation weight gain. The participants (n = 190) were non-diabetic pregnant
women (88 in the control group and 102 in the intervention group). Women of all BMI were recruited and
the results indicated that the intervention reduced excessive gestational weight gain. As the study did not aim
to reduce weight in obese pregnant women, it is excluded
16
(Continued)
Jackson 2011
This is a randomised controlled trial including pregnant women of all BMI, recruited before 26 weeks of
pregnancy, n = 327 (163 in the intervention and 164 usual care). The study was conducted in the US.
The intervention was called ’Video Doctor’ - messages about diet, exercise and weight gain delivered by
actor portrayed DVD delivered on a laptop in the clinic setting versus usual care. The primary outcome was
improvements in women’s diet and exercise behaviours, and weight gain was a secondary outcome. The results
indicate that there were statistically significant increases from baseline in exercise undertaken and consumption
of healthy foods, and significant decreases in unhealthy foods. There was no difference in weight gain between
the groups. The intervention did not aim to reduce weight in obese pregnant women and so has been excluded
Jeffries 2009
This is a randomised controlled trial including pregnant women of all BMI, recruited at 14 weeks of pregnancy,
n = 236 (46 of participants had BMI > 29 kg/m2 ). The study was conducted in Australia.The intervention
was a personalised weight measurement card and advice about optimal weight gain in pregnancy with advice
to self-record weight at 4 weekly intervals versus standard antenatal care. All women were weighed at 36 weeks
using the same hospital scale. Participants were blinded to the purpose of the study.The primary outcome was
weight gain from recruitment till 36 weeks of pregnancy. The results indicate that there was a trend of less
weight gain in the intervention group in all BMI categories of participants, except for those with a BMI >
29 kg/m2 . The intervention did not aim to reduce weight in obese pregnant women, but to reduce excessive
weight gain and so has been excluded
Koushkie 2003
This is a brief conference abstract describing a randomised controlled trial designed to assess the effect of an
aerobic exercise programme started in the third trimester on pregnancy outcomes. The participants were 26
pregnant women. It is not clear whether they were obese or not. The outcomes were gestational age, gestational
pregnancy weight gain, and changes in triceps skin thickness. The results indicate that there were no significant
differences between groups. No other publications related to this study have been found. The intervention did
not aim to reduce weight in obese pregnant women, and so has been excluded
Krummel 2009
This study was accessed from the ClinicalTrials.gov where it states that the trial started April 2009 in the US
(NCT00865683). The randomised trial will recruit pregnant women with a BMI greater than 25, however,
it is not clear how many are to be included in the study. The intervention is a nutritional supplement,
docosahexaenoic acid (DHA) versus placebo. The primary outcome is insulin sensitivity measured at month
3. Secondary outcome is interleukin - 6 (IL-6) measured at month 3. The authors have been emailed to find
out more about the study but no reply has been obtained. As the intervention is not designed to reduce weight
in obese pregnant women, the study is excluded
Lavender 2011
This is a pilot randomised controlled trial accessed from Current Controlled Trials (ISRCTN09432573). The
study was conducted in the UK. The intervention is a 10-week lifestyle programme incorporating behaviour
change theory versus routine maternity care. 72 participants are to be recruited. The study is designed to explore
the feasibility and acceptability of the study, and the health of participants. Weight loss is not an outcome.
The intervention did not aim to reduce weight in obese pregnant women, and so has been excluded
Lombard 2011
This is brief conference abstract of a randomised controlled trial from Australia. The intervention was the
delivery of a self-management lifestyle plan with advice to self-weigh (n = 106). The control group (n = 99)
received normal advice about diet and exercise, and no recommendations to weigh themselves. The participants
(n = 205) were pregnant women with BMI greater than 25 kg/m2 , or 23 kg/m2 if they were high risk
according to their ethnic identity. The results indicated that self-weighing has an effect on less weight gain
when incorporated with a self-management lifestyle intervention. However, as the intervention was not aimed
to reduce weight in obese pregnant women, it is not included in this review
17
(Continued)
Louie 2011
This was a randomised controlled trial in Australia. The aim of the study was to investigate the effectiveness
of a low glycaemic versus a high fibre diet on pregnancy and neonatal outcome in women diagnosed with
gestational diabetes mellitus in pregnancy. The outcomes were birthweight, infant parameters, and serum
glucose levels. However, none of the participants recruited were obese at recruitment according to the paper
so the study is excluded
Luoto 2011
This is a cluster-randomised controlled trial in Finland. The intervention included an individualised counselling
programme from weeks 12 to 37 of pregnancy. The counselling involved advice on physical activity, diet and
weight gain in pregnancy. The participants were pregnant women with a high risk of developing gestational
diabetes mellitus and included those with BMI > 25 kg/m2, those with gestational diabetes mellitus or any sign
of glucose intolerance, and those with neonatal macrosomia in past pregnancies. Women who had a family
history of diabetes were also eligible. The primary outcome was the proportion of women who had gestational
diabetes mellitus at 28 weeks of pregnancy and neonatal macrosomia. The secondary outcome was maternal
weight gain. The intervention did not aim to reduce weight in obese women so has been excluded from the
review
Magee 1990
This study is a small randomised controlled trial in the US. The 12 participants were all pregnant women
diagnosed with gestational diabetes mellitus and a prepregnancy weight greater than 120% than their ideal
weight. The study involved hospitalisation for 2 weeks and all participants consumed the same 2400 calorie/
day diet for 1 week. During week 2, the intervention group consumed 1200 calories/day and the control group
carried on with the same 2400 calorie/day diet. The aim of the study was to examine the efficacy of lowering
plasma glucose levels and to better understand metabolic changes in obese women with gestational diabetes
mellitus. Outcomes measurements were serum glucose and other biomarkers relevant to diabetes. At the end
of the study, The results indicated that there was an improvement in glycaemic status in diets of 1200 calories/
day in obese pregnant women with gestational diabetes, but these diets also cause significant ketonemia and
ketonuria. As the intervention did not aim to reduce weight in obese pregnant women, it is excluded
Moholdt 2011
This paper is a protocol of a randomised controlled trial in Norway. The study is ongoing and expected to
be completed end of 2012. The participants will be obese pregnant women (n = 150) and the intervention
is an organised exercise programme designed for pregnant women; the control group will have usual care.
The primary outcome is to reduce weight gain in pregnancy, not reduce weight, hence the study will not be
included in this review
Moses 2006
This study was a parallel controlled trial in the US, where participants were assigned alternatively to each
group. Randomisation did not occur as the participants were alternately assigned to 1 of 2 diets. One diet was
a low glycaemic (carbohydrate) diet and the other a high fibre with moderate - high glycaemic index. Healthy
pregnant women were recruited however, none of the participants were obese. The study has been excluded as
this was not a randomised controlled trial, the participants were not obese and the study did not aim to reduce
weight
Moses 2009
This is a randomised controlled trial in the US. The study included 63 pregnant obese women who were
diagnosed with gestational diabetes mellitus between 28 and 32 weeks of pregnancy. The aim of the study was
to assess whether a low-glycaemic index diet in women with gestational diabetes mellitus reduced the need for
insulin with no compromise on obstetric and fetal outcomes. Maternal weight gain and ponderal index and
obstetric outcomes of induction, birth mode, gestational age, and fetal outcomes of birthweight were assessed.
The results indicated that there was no significant differences between groups in all outcomes. The outcomes
were not related to reducing weight in obese pregnant women so the study has been excluded
18
(Continued)
Nagle 2011
This paper is a protocol of a randomised controlled trial in Australia. The participants will be obese primigravid
pregnant women and the intervention will be continuity of midwifery care (care delivered by a small group of
midwives) in pregnancy versus usual care The study aims to compare both patterns of maternity care provision
on restricting excessive weight gain in pregnancy. The outcomes will be gestational weight gain, women’s
experience of care, satisfaction with care, psychological factors in pregnancy and readiness to change lifestyle.
As the study will not aim to reduce weight in obese pregnant women, it is excluded
Nascimento 2011
This is a randomised controlled trial from Brazil. The participants were 82 pregnant women with BMI greater
than 26 kg/m2 . 42 women were randomised to the intervention group of exercise under supervision, and
another 40 women had usual care in the control group. The primary outcome was an evaluation of weight
gain, not weight reduction, and secondary outcomes included perinatal outcomes such as mode of birth and
birthweight. The results illustrated that the exercise programme was not associated with managing weight gain
across all weights, however, for those who were in the overweight category, there were some benefits in relation
to lowering gestational weight gain. This study has been excluded as the aim was not to reduce weight in obese
pregnant women
Norman 2010
This is a multi-centre randomised controlled trial accessed from Current Controlled Trials (ISRCTN51279843), known as EMPOWaR. The aim of the study is to explore if metformin given to obese
pregnant women will reduce the future life risk of obesity and metabolic syndrome in babies. The participants
will be Caucasian obese pregnant women. The intervention is metformin given 3 times daily to a maximum
of 500-2500 mg each day versus placebo. The primary outcome is birthweight centiles of the baby, correlation
of maternal insulin resistance assessed at 36 weeks’ gestation, and adverse pregnancy outcomes. Although the
secondary outcomes include maternal anthropometry measures the study does not aim to reduce weight in
obese pregnant women. The study is therefore excluded
Ong 2009
This small randomised controlled trial in Australia aimed to explore the impact of a home-based supervised
exercise programme (use of a stationary exercise cycle) over 10 weeks in pregnancy on glucose tolerance
and anaerobic fitness in previously sedentary obese women. The control group continued with their normal
activities. The outcomes were body mass, glucose and insulin responses and aerobic fitness. The results indicated
that regular aerobic exercise may have favourable effects on glucose tolerance and aerobic fitness in obese
pregnant women. However, the study did not aim to reduce weight in obese pregnant women, so is excluded
Parat 2009
This study was accessed from ClinicalTrials.gov (NCT00804765). The study is in France and is a randomised
controlled trial where the intervention is educational sessions at 20, 28 and 35 weeks of pregnancy and then
at 2 months following the birth. The education sessions provide advice on healthy eating and modest exercise.
The control group has usual care and 1 dietary counselling session at 26 weeks of pregnancy. The participants
will be women with a BMI > 25 kg/m2 and it is expected that 800 will be recruited. The primary outcome
is 30% reduction in infant weight gain at 2 years. Secondary outcomes are reduction in rapid weight gain
from 0-6 months, reduction in children with BMI > 19 kg/m2 at 2 years, reduction in incidence of pregnancy
complications and macrosomia, spontaneous feeding at 4 months, increase in breastfeeding, reduction in
maternal BMI at 1 and 2 years after the birth, and reduction in serum lipid and glycaemia at 2 years after the
birth. The authors have been emailed to ask for further information about the intervention, and whether it is
aimed at reducing weight in obese women, and there has been no reply. The study has been excluded as the
intervention does not clearly state that it is aimed at reducing weight in obese pregnant women
Phelan 2011
This was a randomised controlled trial aimed at decreasing the proportion of pregnant women who exceeded
1990 IOM guidelines for gestational weight gain and to increase the proportion of women who had reached
their pre gravid weight at 6 months after the birth of their babies. The intervention was a behavioural-based
19
(Continued)
educational package designed to prevent excessive weight gain in pregnancy versus usual care. The study was
completed in the US. 400 women were recruited. The primary outcomes were the proportion of pregnant
women with an excessive weight gain based on the 1990 IOM guidelines and proportion of women below
their pre gravid weight 6 months after the birth. The study did not aim to reduce weight in obese pregnant
women, so is excluded from the review
Polley 2002
This study is a randomised controlled trial aimed at exploring whether a stepped-care behavioural lifestyle
intervention incorporating information about weight gain in pregnancy, healthy exercise and eating will reduce
excessive weight gain in pregnancy. The study was completed in the US. 120 pregnant women with a BMI > 19.
8 kg/m2 participated. The primary outcome was the proportion of women who exceeded the IOM guidelines
in relation to weight gain in pregnancy. The secondary outcomes were to evaluate the effects on total weight
gain, weight gain from recruitment to birth, and after the birth, weight loss and weight retention. The results
were stratified according to BMI and indicated that normal - weight women were less likely to exceed the IOM
guidance in relation to weight gain in pregnancy (P < 0.05), but in the overweight women (BMI > 26.0 kg/m2 )
there was a non-significant trend (P = 0.09) in the opposite direction where 59% of those in the intervention
group gained weight in excess of the IOM guidelines compared to 32% in the control group. The study did
not aim to reduce weight in obese pregnant women, so is excluded from the review
Poston 2009
This is a randomised controlled trial accessed from the Current Controlled Trials (ISRCTN8997135). The
study is being conducted in the UK. The goal of the study is to develop an intervention (individualised
pregnancy activity and diet programme) that will improve maternal glucose sensitivity in obese pregnant
women carrying a singleton fetus and lead to minimising maternal, fetal and neonatal complications. One
hundred pregnant women are to be included. The study does not aim to reduce weight in obese pregnant
women, so is excluded from the review
Quinlivan 2011
This was a randomised controlled trial of a 4-stepped multidisciplinary intervention including a food technologist and clinical psychologist in pregnancy versus usual antenatal care. The study was completed in Australia.
The aim of the study was to evaluate if the intervention would reduce the incidence of gestational diabetes
mellitus. The participants were 134 overweight and obese pregnant women. The primary outcome is prevalence of gestational diabetes mellitus and decreased gestational glucose tolerance. The secondary outcomes are
weight gain in pregnancy and birthweight. There was a significant decrease in incidence of gestational diabetes
mellitus (P =< 0.04) and reduction in weight gain in pregnancy (P < 0.0001) in the intervention group. The
study did not aim to reduce weight in obese pregnant women, so is excluded from the review
Rae 2000
This was a randomised controlled trial conducted in Perth, Australia. The participants were pregnant women
who were > 110% of ideal body weight for their height (where a BMI of 25 kg/m2 was considered equal to
100% of their ideal body weight) n = 117, 63 in the intervention and 54 in the control group. The intervention
was a moderately energy restricted diabetic diet providing 1590-1776 kilocalories a day (70% of recommended
dietary intake in Australia). The control group followed a diabetic diet that was not energy restricted and
provided 2010-2220 kilocalories a day. The aim of the study was to determine the effect of a 30% maternal
dietary energy restriction on the need for maternal insulin and incidence of macrosomia. Outcomes were
weight gain, energy intake, blood glucose levels, birthweight, gestation at birth, mode of birth. It is reported
that more women in the intervention group lost weight than those in the control group although this is not
statistically significant. The mean weight lost in the intervention group was 1.68 kg (SE 0.33, range 7.50-0.
00), and 1.68 kg (SE 0.32, range 5.00-0.00) in the control group. The author of the study was emailed to
confirm the aim of the study. The study did not aim to reduce weight in obese pregnant women so has been
excluded from the study
20
(Continued)
Rhodes 2010
This study was a randomised controlled trial in the US. The participants were 46 overweight and obese pregnant
women (BMI were > 25 kg/m2 and < 45 kg/m2 ). The intervention group were allocated to a low fat diet and
control group, a low glycaemic diet. The primary outcome was birthweight and secondary outcomes were
maternal weight gain and body composition, presence of maternal cardiovascular disease risk factors, gestational
length and infant anthropometric measurements. The results indicate that there were no significant differences
between maternal weight or maternal anthropometric measurements at 36 weeks. There were no significant
differences in birthweight although infant skinfold thickness measurements were lower (not significant) in the
low glycaemic diet group. The principal investigator was contacted to clarify if maternal weight reduction was
an outcome and this correspondence confirmed that weight gain was a secondary outcome. As maternal weight
reduction was not an outcome, the study has been excluded
Santos 2005
This study was a randomised controlled trial in Brazil. The intervention was supervised physical exercise of
60 minutes duration carried out 3 times weekly. The control group took part in once a week relaxation and
light stretching sessions. Altogether, 92 healthy pregnant women with BMI from 26-31 kg/m2 participated (46
in each group). The primary outcome was submaximal exercise capacity that was assessed by oxygen uptake
at the anaerobic threshold after 12 weeks of completion. Secondary outcomes included respiratory exchange
ratio, carbon dioxide output and heart rate at the anaerobic threshold. Birth weight was also assessed. The
intervention was not designed to reduce weight in obese women so has been excluded from the review
Shehata 2012
This is a randomised controlled trial accessed from ClinicalTrials.gov (NCT01273584). The study is being
conducted in the UK and recruitment of 850 pregnant women with BMI > 35 kg/m2 commenced Autumn
2010 and continues till Autumn 2014. The intervention includes metformin three times day with each meal
whilst the control group is a placebo. The primary outcome is birth weight and secondary outcomes include
maternal weight gain, development of gestational diabetes and hypertension, incidence of caesarean section,
post partum haemorrhage and neonatal complications such as preterm birth. The study does not aim to reduce
weight in obese pregnant women, so is excluded from the review
Silverman 1971
This was a randomised controlled trial (double blinded) in the US. The intervention was an appetite depressant
drug diethylpropion hydrochloride and the control was a placebo.The study included 75 pregnant women who
were described as overweight, or gaining weight excessively. Each participant was prescribed a 1500 calorie diet.
However, calculation of the BMI from the mean weight and height reported in the paper of the 75 participants
indicated that these were not obese (22 kg/m2 in the intervention group and 23 kg/m2 in the control group).
As the participants were not obese, the study is excluded
Szmeja 2011
This is a brief abstract of a randomised controlled trial with overweight and obese pregnant women (n = 193)
carried out in Australia. The intervention was a DVD incorporating dietary advice. The outcome measures
were self-reported knowledge and satisfaction with care. The study was not aiming to reduce weight in obese
pregnant women, hence is not included in this review
Te Morenga 2010
This study was a randomised controlled trial. Although the interventions were aiming to reduce weight in
obese women, the participants in the study were not pregnant. Hence the study has been excluded
Teede 2011
This is brief conference abstract of a randomised controlled trial in Australia. 228 overweight women at risk
of developing gestational diabetes mellitus were recruited. The intervention was a 4-phase lifestyle behavioural
programme aimed to increase physical activity and the control group participants received 1 physical activity
session. The primary outcome was optimising physical activity.The preliminary results indicate that this behavioural intervention in pregnancy may help minimise decline in physical activity in pregnancy compared to
information on its own. However, this study was not aiming to reduce weight in obese pregnant women so
21
(Continued)
will not be included in this review
Thornton 2009
This study was a randomised parallel-group controlled trial carried out in the US. The participants were
232 healthy pregnant obese women who were randomised into 2 groups. Exclusion criteria included women
suffering from medical complications including pre-existing diabetes. The intervention group followed a diet
similar to that provided to women who would have been diagnosed with diabetes mellitus (minimum of 2000
calories a day). The control group followed conventional dietary management. The objectives of the study were
to compare perinatal outcomes between groups, determine the effects of weight stabilisation between groups,
determine perinatal differences in the intervention group between adherence and non-adherence, evaluate
perinatal outcomes in women who gained less than 15 pounds, and those who gained more than 15 pounds
across both groups. The results indicated that there were statistically significant differences between groups
in relation to developing gestational hypertension (P < 0.46), maternal last weight before birth (P < 0.001),
and maternal 6 week postpartum weight (P < 0.001). Women gaining more than 15 pounds were statistically
significantly more likely to have babies that were heavier, develop gestational diabetes, pre-eclampsia, undergo
caesarean section and have labour induced. It is reported that 22 women lost weight who took part in this
study but it is not clear which group they were in. The study did not plan to reduce weight in obese pregnant
women so has been excluded
Vinter 2011
This was a randomised controlled trial from Denmark. 360 obese pregnant women were included; 150 were
randomised to the intervention of dietary counselling from dieticians on 4 occasions and physical activity, and
154 were randomised to the control group which included routine information about the study and access
to a web site on diet and exercise. The primary outcome was to limit gestation weight gain to 5 kilograms in
obese pregnant women, not reduce weight. The results indicated that obstetric outcomes were not significantly
different in both groups. The intervention group had a significantly lower median range of gestational weight
gain compared to the control group. However, as the study did not aim to reduce weight in obese pregnant
women, it has been excluded from this review
Vitolo 2011
This was a randomised controlled trial in Brazil.The participants were healthy pregnant women, n = 315, (n =
156 in the intervention group and n = 159 in the control group). The intervention was dietary advice according
to whether the participant was low weight, normal weight or over weight and the control group had no extra
dietary advice. The aim of the study was to explore weight gain during pregnancy. The results indicated that
weight gain for those who were overweight and in the intervention group was less than those of similar weight
in the control group. It is not clear if the participants were obese, and as maternal weight reduction was not
an outcome, the study has been excluded
Wolff 2008
This was a randomised controlled trial in Denmark. The aim of the study was to explore if restricting gestational
weight gain in obese pregnant women can reduce pregnancy-induced elevations of insulin, leptin and glucose.
50 pregnant obese women took part (n = 23 in the intervention group and n = 27 in the control group). The
intervention was 10 consultations of 1 hour duration with a dietician during the pregnancy. Advice was given
according to Danish dietary recommendations. The control group had usual care and no restrictions on energy
intake and weight gain. The results indicated that the intervention group participants limited their energy
intake, and restricted gestational weight gain to 6.6 kg. The control group gained 13.3 kg. The intervention
was not designed to reduce weight in obese women so has been excluded from the review
BMI: body mass index
IOM: Institure of Medicine
22
DATA AND ANALYSES
This review has no analyses.
APPENDICES
Appendix 1. Methods for updating the review
Data extraction and management
We will design a form to extract data. For eligible studies, at least two review authors will extract the data using the agreed form. We
will resolve discrepancies through discussion or, if required, we will consult a third person. We will enter data into Review Manager
software (RevMan 2011) and check for accuracy.
When information regarding any of the above is unclear, we will contact authors of the original reports to provide further details.
Assessment of risk of bias in included studies
Three review authors (C Furber, T Lavender, and L McGowan) will independently assess risk of bias for each study using the criteria
outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We plan to resolve any disagreement by
discussion.
(1) Random sequence generation (checking for possible selection bias)
We will describe for each included study the method used to generate the allocation sequence in sufficient detail to allow an assessment
of whether it should produce comparable groups.
We will assess the method as:
• low risk of bias (any truly random process, e.g. random number table; computer random number generator);
• high risk of bias (any non-random process, e.g. odd or even date of birth; hospital or clinic record number);
• unclear risk of bias.
(2) Allocation concealment (checking for possible selection bias)
We will describe for each included study the method used to conceal allocation to interventions prior to assignment and will assess
whether intervention allocation could have been foreseen in advance of, or during recruitment, or changed after assignment.
We will assess the methods as:
• low risk of bias (e.g. telephone or central randomisation; consecutively numbered sealed opaque envelopes);
• high risk of bias (open random allocation; unsealed or non-opaque envelopes, alternation; date of birth);
(3.1) Blinding of participants and personnel (checking for possible performance bias)
We will describe for each included study the methods used, if any, to blind study participants and personnel from knowledge of which
intervention a participant received. We will consider that studies are at low risk of bias if they were blinded, or if we judge that the lack
of blinding would be unlikely to affect results. We will assess blinding separately for different outcomes or classes of outcomes.
• low, high, or unclear risk of bias for participants;
• low, high, or unclear risk of bias for personnel.
23
(3.2) Blinding of outcome assessment (checking for possible detection bias)
We will describe for each included study the methods used, if any, to blind outcome assessors from knowledge of which intervention a
participant received. We will assess blinding separately for different outcomes or classes of outcomes.
We will assess methods used to blind outcome assessment as:
• low, high, or unclear risk of bias.
(4) Incomplete outcome data (checking for possible attrition bias due to the amount, nature and handling of incomplete
outcome data)
We will describe for each included study, and for each outcome or class of outcomes, the completeness of data including attrition and
exclusions from the analysis. We will state whether attrition and exclusions are reported and the numbers included in the analysis at
each stage (compared with the total randomised participants), reasons for attrition or exclusion where reported, and whether missing
data were balanced across groups or were related to outcomes. Where sufficient information is reported, or could be supplied by the
trial authors, we will re-include missing data in the analyses which we undertake.
We will assess methods as:
• low risk of bias (e.g. 20% or less missing outcome data; missing outcome data balanced across groups);
• high risk of bias (e.g. greater than 20% missing data; missing data imbalanced across groups; ‘as treated’ analysis done with
substantial departure of intervention received from that assigned at randomisation);
(5) Selective reporting (checking for reporting bias)
We will describe for each included study how we will investigate the possibility of selective outcome reporting bias and what we find.
• low risk of bias (where it is clear that all of the study’s pre-specified outcomes and all expected outcomes of interest to the review
have been reported);
• high risk of bias (where not all the study’s pre-specified outcomes have been reported; one or more reported primary outcomes
were not pre-specified; outcomes of interest are reported incompletely and so cannot be used; study fails to include results of a key
outcome that would have been expected to have been reported);
(6) Other bias (checking for bias due to problems not covered by (1) to (5) above)
We will describe for each included study any important concerns we have about other possible sources of bias.
We will assess whether each study is free of other problems that could put it at risk of bias:
• low risk of other bias;
• high risk of other bias;
• unclear whether there is risk of other bias.
(7) Overall risk of bias
We will make explicit judgements about whether studies are at high risk of bias, according to the criteria given in the Handbook (Higgins
2011). With reference to (1) to (6) above, we will assess the likely magnitude and direction of the bias and whether we consider it
likely to impact on the findings. We will explore the impact of the level of bias through undertaking sensitivity analyses - see Sensitivity
analysis.
Measures of treatment effect
Dichotomous data
For dichotomous data, we will present results as summary risk ratio with 95% confidence intervals.
24
Continuous data
For continuous data, we will use the mean difference if outcomes are measured in the same way between trials. We will use the
standardised mean difference to combine trials that measure the same outcome, but use different methods. If there is evidence of
skewness, we will report this in the text.
Unit of analysis issues
Cluster-randomised trials
We will include cluster-randomised trials in the analyses along with individually-randomised trials. We will adjust their sample sizes
using the methods described in the Handbook using an estimate of the intracluster correlation co-efficient (ICC) derived from the
trial (if possible), from a similar trial or from a study of a similar population. If we use ICCs from other sources, we will report this
and conduct sensitivity analyses to investigate the effect of variation in the ICC. If we identify both cluster-randomised trials and
individually-randomised trials, we plan to synthesise the relevant information. We will consider it reasonable to combine the results
from both if there is little heterogeneity between the study designs and the interaction between the effect of intervention and the choice
of randomisation unit is considered to be unlikely.
We will acknowledge heterogeneity in the randomisation unit and perform a sensitivity analysis to investigate the effects of the
randomisation unit.
Cross-over trials
We will not include cross-over trials as these are not an appropriate study design for the interventions in this review.
Other unit of analysis issues
Studies with multiple pregnancies
If we include studies involving multiple pregnancies, we will treat the infants as independent and note effects of estimates on confidence
intervals in the review.
Studies with more than two treatment groups
If we include studies using one or more treatment groups (multi-arm studies), where appropriate, we will combine groups to create a
single pair-wise comparison. We will use methods described in the Handbook (Higgins 2011) to ensure that we do not double count
participants.
Dealing with missing data
For included studies, we will note levels of attrition. We will explore the impact of including studies with high levels of missing data in
the overall assessment of treatment effect by using sensitivity analysis.
For all outcomes, we will carry out analyses, as far as possible, on an intention-to-treat basis, i.e. we will attempt to include all participants
randomised to each group in the analyses, and analyse all participants in the group to which they were allocated, regardless of whether
or not they received the allocated intervention. The denominator for each outcome in each trial will be the number randomised minus
any participants whose outcomes are known to be missing.
Assessment of heterogeneity
We will assess statistical heterogeneity in each meta-analysis using the T², I² and Chi² statistics. We will regard heterogeneity as
substantial if T² is greater than zero and if I² estimates are moderate or high (low if I² = 25%, moderate if I² = 50% and high if I² =
75%) or there is a low P value (less than 0.10) in the Chi² test for heterogeneity.
25
Assessment of reporting biases
If there are 10 or more studies in the meta-analysis, we will investigate reporting biases (such as publication bias) using funnel plots.
We will assess funnel plot asymmetry visually, and use formal tests for funnel plot asymmetry. For continuous outcomes we will use the
test proposed by Egger 1997, and for dichotomous outcomes we will use the test proposed by Harbord 2006. If we detect asymmetry
in any of these tests or by a visual assessment, we will perform exploratory analyses to investigate it.
Data synthesis
We will carry out statistical analysis using the Review Manager software (RevMan 2011). We will use fixed-effect meta-analysis for
combining data where it is reasonable to assume that studies are estimating the same underlying treatment effect: i.e. where trials are
examining the same intervention, and the trials’ populations and methods are judged sufficiently similar. If there is clinical heterogeneity
sufficient to expect that the underlying treatment effects differ between trials, or if we detect substantial statistical heterogeneity, we
will use random-effects meta-analysis to produce an overall summary if an average treatment effect across trials is considered clinically
meaningful. We will treat the random-effects summary as the average range of possible treatment effects and we will discuss the clinical
implications of treatment effects differing between trials. If the average treatment effect is not clinically meaningful, we will not combine
trials.
If we use random-effects analyses, we will present the results as the average treatment effect with its 95% confidence interval, and the
estimates of T² and I².
Subgroup analysis and investigation of heterogeneity
If we identify substantial heterogeneity, we will investigate it using subgroup analyses and sensitivity analyses. We will consider whether
an overall summary is meaningful, and if it is, use random-effects analysis to produce it.
We plan to carry out the following subgroup analyses.
1. Pre-pregnancy BMI (morbidly obese versus obese).
2. Primigravidae versus multigravidae.
3. Women under 20 years of age versus those over 20 years of age.
4. Low-income settings versus high-income settings.
We will use the following outcomes in subgroup analysis:
• serious maternal and neonatal morbidity/death;
• weight (loss/gain/no change).
We will assess differences between subgroups by interaction tests and by inspection of the subgroups’ confidence intervals; nonoverlapping confidence intervals indicate a statistically significant difference in treatment effect between the subgroups.
Sensitivity analysis
We will carry out sensitivity analyses as appropriate to evaluate the effect of trial quality.
CONTRIBUTIONS OF AUTHORS
Christine Furber and Tina Lavender conceived and designed the review.
Christine Furber wrote the protocol.
Tina Lavender, Linda McGowan, Siobhan Quenby, Peter Bower, and Evangelos Kontopantelis contributed significant input to the text
and carefully reviewed drafts of the protocol.
26
DECLARATIONS OF INTEREST
None known.
SOURCES OF SUPPORT
Internal sources
• The University of Manchester, UK.
External sources
• National Institute of Health Research, UK.
NIHR NHS Cochrane Collaboration Programme grant scheme award for NHS-prioritised centrally-managed, pregnancy and
childbirth systematic reviews: CPGS 10/4001/02
DIFFERENCES BETWEEN PROTOCOL AND REVIEW
We amended the Background to include studies published since the protocol was published, and added other subheadings to make the
section easier to follow.
INDEX TERMS
Medical Subject Headings (MeSH)
∗ Pregnancy
Outcome; ∗ Weight Loss; Obesity [∗ therapy]; Pregnancy Complications [∗ therapy]; Prenatal Care [∗ methods]
MeSH check words
Female; Humans; Pregnancy
27

Antenatal interventions for reducing weight in obese women The Cochrane Library

Transcription

Similar documents

21 Reasons to See a Gynecologist Before Age 21 Infographic

Am I pregnant? Signs and symptoms

PregnAncY AnD Your VISIon

Neotigason(acitretin) 10 mg and 25 mg capsules

INDEMNITY: EXPECTANT MOTHERS Please complete

Philadelphia Pregnancy Accommodations (e2525)

4th international ESPCOP Meeting

August 24, 2015 - Care New England Health System

TIPS for Screening Pregnant Women

Who is this summary for?