Process
and Stages
of
Labor and Birth
Chapter 17
LABOR
The Process by
which the Products of
Conception are expelled
from the body
THE
Birth
PASSAGE
THE PELVIS
False Pelvis


Supports the
weight of the
uterus
Shallow basin
above the inlet
or brim
True Pelvis
 Represents
the bony
limits of the
birth canal
True Pelvis vs. False Pelvis
True Pelvis
Inlet - upper margin of pubic bone to
upper margin of sacrum
Outlet - Lower pubic bone to tip of
coccyx. This area is the
smallest portion that the baby
must travel through.
The
Fetus
Fetal Head
Because of its size and rigidity,
the Fetal Head has a major
impact on delivery.
The bones are not firmly united.
There are sutures between the
bones that allow them to
overlap or MOLD to the birth
canal.
Head also can rotate, flex, and
extend
Attitude
Relationship
of fetal body
parts to
each other
Optimum
attitude is
ovoid
The head is flexed forward, with the chin almost resting on the chest. The arms
and legs are flexed.
Fetal Lie
Relationship of the long axis of the fetus
to the long axis of the mother.
Longitudinal Lie
Transverse Lie
True or False?
The optimum lie of the fetus is the
longitudinal lie.
A. True
B. False
Fetal Presentation
That portion of the fetus that enters the
Pelvis first and covers the internal os.
Three Types:
Cephalic
Vertex, Face, Brow
Breech
Shoulder
Cephalic Presentation
The head is entering
the pelvis first.
Reference Points
Cephalic = Occiput, posterior fontanel
Breech = Sacrum
Face = Mentum
Engagement
Engagement
Ballotable
-largest diameter of
presenting part has
passed through the
pelvic inlet
-
Assessed during
vaginal exam
Engaged
Station
Station- degree that the
presenting part has
descended into the pelvis
in
Relationship to ischial
spines
Goal
•
Move from – to + stations
POSITION
Relationship of the Fetal Presenting Part
to the Maternal Pelvis
Steps:
1. Determine the Presenting Part
2. Divide the mothers pelvis into 4 imaginary quadrants
A
12
R
9
3
6
P
L
Test Yourself !
What is the reference point of a cephalic
presentation when the head is fully
flexed?
A.
B.
C.
d.
occiput
mentum
frontal
sagittal
Test Yourself
Overlapping of the fetal skull to facilitate its
passage through the bony pelvis is ___________.
Relationship of fetal body parts to each other
is_____________.
Head first presentation is_________________.
Relationship of the fetal spine to the maternal
spine is ________________.
Term that refers to the part of the fetus that
enters the pelvic inlet first is _____________.
The
Physiologic
Forces of Labor
Major Powers Involved
Involuntary Uterine Contractions or
Primary Powers
Muscular contractions which lead to dilation
and effacement in the First Stage of Labor
Voluntary Uterine Contractions or
Secondary Powers
Abdominal muscles assist in the Second Stage
with pushing. Increase intra-abdominal
pressure to aid in expulsive forces
FORCES OF LABOR
Contraction -exhibits a wavelike pattern that
begins slowly climbing (increment) to a peak
(acme), and decreases (decrement)
acme
Duration
Interval
Frequency
Duration- from beginning of one contraction to the end of the same
contraction
Frequency- from beginning of one contraction to the beginning of
another contraction
Interval - Resting time between contractions for placental perfusion
Fill in the Blank
Length of a uterine contraction__________.
Strength of a uterine contraction is ___________.
The time from the beginning of one contraction to
the beginning of the next contraction is _______.
The time that allows for placental perfusion is __.
The peak of a contraction is also known as ____.
When the biparietal diameter of the head passes
through the pelvic inlet it is said to be ________.
PSYCHOLOGICAL
Considerations
BREAK THE CYCLE !
FEAR
TENSION
PAIN
CAUSES OF LABOR
Progesterone Withdrawal
High levels of
Prostagladins
Corticotropin-Releasing Hormone
Myometrial Activity
Effacement- thinning of the cervix (%)
Dilation – enlargement and widening of the os (cm)
Critical Thinking
If the fetal head did not descend through
the pelvis and stayed at the same station
for a prolonged period of time, what do
you think would be the treatment of
choice?
Try this !
When the cervical os widens or opens it is said
to________.
The level of the ________ _________ is station zero.
The most common type of pelvis for a woman
___________.
When the cervix shortens and thins is _______________.
For delivery to occur, the fetus must accomodate to this
rigid passageway______________.
Premonitory Signs of Labor
The impending signs
that take place the last
several weeks of
pregnancy or even the
last several days
Premonitory Signs of Labor
LIGHTENING
BRAXTON-HICKS CONTRACTIONS
CERVICAL CHANGES
SHOW
ROM
BACKACHE
SUDDEN INCREASE IN ENERGY
True vs. False Labor

TRUE LABOR
Contractions are:
* Regular
*Increase in intensity and
duration with walking
*Felt in lower back,
radiating to lower
portion of abdomen
 Bloody show
 Dilation and effacement
 Fetus usually engaged


FALSE LABOR

Contractions are
irregular
Often stop with walking
Contractions felt in
abdomen above
umbilicus (abdominal
pains)
No change in cervix
Fetus is ballotable




Phases and Stages of Labor
Stage 1 – From 0 cm. dilated to 10 cm.
Stage 2 - From complete dilation and
effacement to delivery of the
baby
Stage 3 - From delivery of baby to the
delivery of the placenta
Stage 4 - the first hour after delivery
Phases of First Stage of Labor
Latent Phase – is from 0 to 3 cm. dilated
Active Phase – is from 4cm. to 7 cm.
Transistion Phase – is from 8 cm. to 10 cm.
Signs of Second Stage of Labor
Complete dilatation of cervix
Urge to bear down
Perineum begins to bulge, flatten and
move anteriorly
Increase in bloody show
Rectal pressure
Labia begins to part with each contraction
Mechanisms of Labor/
Cardinal Movements
Descent
Flexion
Internal Rotation
Extension
External Rotation
Expulsion
Signs of Stage Three of Labor
Globular
Shape of Uterus
Protrusion of
Umbilical cord
Fundus Rise in
Abdomen
Sudden Gush of
Blood
The End