I attribute my success to this: I never gave or took

9/28/2015
Samantha A. Sommerness DNP, APRN, CNM
Clinical Assistant Professor
University of Minnesota School of Nursing
Describe the overall physiology of a uterine
contraction and how the three p’s: the powers, the
passenger and the passage work together to achieve
complete dilation and expulsion.
List two physiologic benefits of open glottis pushing
for both mom and baby.
State two ways to improve second stage labor
support and initial steps to moving away from
directed pushing on your labor and delivery unit.
“I attribute my success to this: I
never gave or took any excuse”
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So Why Do I Care so
Much About the Second
Stage….
Two phases to the Second Stage
Phase I: “the lull”
or Latent phase:
From complete
dilatation until the
urge to bear down
Phase II: Active
phase or pushing
phase: From the
onset of active
pushing efforts to
crowning of the
presenting part
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Cardinal movements through the Curve of
Carus (we will focus steps 2-4):
1. Head floating, before engagement
2. Engagement, descent, flexion
3. Further descent, internal rotation
4. Complete rotation, beginning extension
5. Complete extension,
6. Restitution (external rotation)
7. Delivery of anterior shoulder
8. Delivery of posterior shoulder
Cardinal movements through the Curve of
Carus (we will focus steps 2-4):
Pushing too early without the urge to
push, not only leads to exhaustion,
but works against the natural curve of
the maternal spine
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Lack of standardization of management of the length of the
second stage of labor
Inconsistent use of operative vaginal delivery bundle
Fetal heart rate patterns are managed differently in the second
stage than in the first stage
Inadequate fetal monitoring in second stage
Failure to rescue in the second stage
Lack of documentation in second stage
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Forces of the contractions
it is dependent on the intense and complex interactions
with the variables which make up the mechanical portion of
variables, which are known as the three P’s:
the powers (contractions),
the passenger and the passage. The powers and its
companion the contraction work together to achieve
complete dilation, but without the continuation the
rotation through the birth canal……
the passenger (fetus) will not be able to navigate the
passage (birth canal).
Fundus—rounded upper
part superior to the
entrances of the uterine
tubes
Body (corpus) —upper two
thirds
Isthmus—narrower area just
above the cervix
Cervix (neck) —cylindrical
inferior part that projects
into the superior vagina
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Uterine anatomy is comprised of three tissue layers
The inner layer, called the endometrium, is the most active
layer and responds to cyclic ovarian hormone changes; the
endometrium is highly specialized and is essential to menstrual and
reproductive function
The middle layer, or myometrium, makes up most of the
uterine volume and is the muscular layer, composed primarily of
smooth muscle cells (focus on today)
The outer layer of the uterus, the serosa or perimetrium, is a
thin layer of tissue made of epithelial cells that envelop the uterus
How do these tissue
layers work
together to form a
contraction?
An outer layer which runs
Muscle Fibers
longitudinally and continues through
the fallopian tubes and round
ligaments,
A vascular layer which consists of
coiled smooth muscle and blood
vessels
Inner layer which comprises mainly
smooth muscle fibers arranged both
longitudinally and obliquely
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Tissue Layers
Supported by Ligaments
The top 2/3rd of the uterus (the
body) has muscle fibers going
different directions. The uterus
and heart are smooth muscle
cells.
They are arranged in bundles
of 10-15 cells in a matrix of
connective tissue.
This matrix transmits the forces
of the contractions, and
represents the propulsion
behind the ever powerful
uterine contraction.
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During labor the uterus is divided into two functional
segments: the upper and the lower.
The upper segment or body of the uterus, contracts
strongly and with each successive contraction the smooth
muscle fibers become shorter and thicker. This powerful
segment draws passive lower part of the uterus up over
itself and causes the cervix to dialate.
The lower uterine segment consists of the lower body of
the uterus and the cervix and although it can contract it is
relatively passive compared to the powerful forces of the
upper uterine segment.
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The cervix itself is not conducting any
contractions; it is reacting to them,
allowing the forces to do their job to pull
the uterus up over itself, slowly dilating the
cervix
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Currently AWHONN and ACNM encourages the use of
physiologic bearing down versus sustained breath holding
during expulsive efforts.
“Physiologic bearing down (several short pushes
without breath holding), while resulting in a
slightly longer second stage, may result in
improved maternal/fetal gas exchange and
maternal satisfaction with her birth experience”.
(Varney, 2004)
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The phase of active pushing is usually accompanied by a decline
in fetal pH. By allowing an early phase of rest and fetal descent
and delaying pushing until the woman has an urge to push only
when obstetric conditions are optimal, the decline in fetal pH
will be decreased
(Roberts, 2003).
Traditionally a woman is encouraged to take one or two
cleansing breaths at the start of the contraction and while the
contraction is building. Then she is to take a deep breath and
hold while she pushes for as long as she can. Two or three good
pushes are usual during a contraction
Current issues in our labor and delivery practice
Sustained breath holding combined with prolonged
bearing down may produce fetal hypoxia and acidosis due
to mother’s closed glottis and increased thoracic pressure.
This combination results in a drop in arterial pressure
caused by decreased cardiac output due to diminished
fetal return to the heart.
Decreased arterial pressure has 2 effects:
1. decreases blood flow to the placenta
2. decreases oxygen content in the blood which circulates
to the placenta
Fetal hypoxia may be prevented if the woman is given different
pushing and breathing instructions. (Varney, 2004)
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ACNM and AWHONN: Open-glottis pushing The woman should be told to push simultaneously with a
forced exhalation for short periods of time, usually over 56 seconds
Often accompanied by a grunt….remember the
definition of GRIT, the verb or action….☺
The glottis is at least partially opened, abdominal muscles
are shortened and contracted against the uterus and
*Intrathoracic pressure does not increase to
interfere with venous return*
WHERE do labor units go from here?
1. The elephant in the room….
2. Continuation of doing something that all know is not
beneficial, but remains habit
WAYS to improve labor support and initial steps to moving away
from directed pushing on your labor and delivery unit
1. Establish a provider and nurse champion on your unit
2. Educate by both information (physiology) and leadership
3. Be the example in the room, regardless of how
uncomfortable….
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