Ch.-13-Labor and Birth Process

widely believed that labor is influenced by

uterine stretch from the fetus and amniotic fluid volume, progesterone withdrawal to estrogen dominance, increased oxytocin sensitivity, and increased release of prostaglandins

Prostaglandins lead to

additional contractions, cervical softening, gap junction induction, and myometrial sensitization, thereby leading to a progressive cervical dilation

Dilation is the

opening or enlargement of the external cervical os

Uterine contractions have two main functions:

to dilate the cervix and to push the fetus through the birth canal

Premonitory signs of labor

- Cervical changes

- Lightening

- Increased energy level

- "Bloody show"

- Braxton Hicks contractions

- Spontaneous rupture of membranes

Cervical changes that indicate labor

cervical softening and possible cervical dilation with descent of the presenting part into the pelvis occur.

can occur 1 month to 1 hour before actual labor begins.

cervix changes from an elongated structure to a shortened, thinned segment

Lightening

occurs when the fetal presenting part begins to descend into the true pelvis

usually making breathing much easier and decreasing in gastric reflux but increased pelvic pressure, leg cramping, dependent edema in the lower legs, and low back discomfort

In primiparas- occurs 2 weeks or more before labor begins; multiparas-may not occur until labor starts

Increased energy (nesting)

usually occurs 24 to 48 hours before the onset of labor

Possibly a result of an increase in epinephrine release caused by a decrease in progesterone

Bloody show

mucus plug is expelled causing ruptured capillaries resulting in the pink-tinged secretions known as bloody show

Braxton hicks contractions

may become stronger and more frequent

usually last about 30 seconds but can persist for as long as 2 minutes

Spontaneous rupture of membranes

can result in either a sudden gush or a steady leakage of amniotic fluid.

advise women to notify their health care providers and go in for an evaluation due to possible ascending infections

An infant born between _______ and ______ weeks' gestation is identified as "late preterm" and experiences many of the same health issues as other preterm birth infants

34 0/7 and 36 6/7

Contraction timing for True Labor

Regular, becoming closer together, usually 4-6 minutes apart, lasting 30-60 seconds

Contraction timing for False Labor

Irregular, not occurring close together

Contraction strength for true labor

Become stronger with time, vaginal pressure is usually felt

Contraction strength for false labor

Frequently weak, not getting stronger with time or alternating (a strong one followed by weaker ones)

Contraction discomfort of true labor

Starts in the back and radiates around toward the front of the abdomen

Contraction discomfort of false labor

Usually felt in the front of the abdomen

Any change in activity during true labor

Contractions continue no matter what positional change is made.

Any change in activity during false labor

Contractions may stop or slow down with walking or making a position change.

Stay or go for true labor

Stay home until contractions are 5 minutes apart, last 45-60 seconds, and are strong enough so that a conversation during one is not possible—then go to the hospital or birthing center.

Stay or go for false labor

Drink fluids and walk around to see if there is any change in the intensity of the contractions; if the contractions diminish in intensity after either or both, stay home.

the "five Ps" that affect the labor process

Passageway (birth canal)

Passenger (fetus and placenta)

Powers (contractions)

Position (maternal)

Psychological response

the five ADDITIONAL "P's" can also affect the labor process

Philosophy (low-tech, high-touch)

Partners (support caregivers)

Patience (natural timing)

Patient (client) preparation (childbirth knowledge base)

Pain management (comfort measures)

passageway is

the route through which the fetus must travel to be born vaginally

passageway consists of

the maternal pelvis and soft tissues

when do you assess the pelvis

pelvis is assessed and measured during the first trimester to identify any abnormalities that might hinder a successful vaginal birth

Bony pelvis is divided into

divided into the true and false portions

The false (or greater) pelvis is

composed of the upper flared parts of the two iliac bones with their concavities and the wings of the base of the sacrum.

linea terminalis

an imaginary line drawn from the sacral prominence at the back to the superior aspect of the symphysis pubis at the front of the pelvis that divides the true and the false portions

The true pelvis

is the bony passageway through which the fetus must travel, made up of three planes: the inlet, the mid-pelvis (cavity), and the outlet.

Pelvic inlet

is the entrance toward the birth canal

Mid-pelvis

the space between the inlet and outlet

As the fetus passes through this small area, their chest is compressed, causing lung fluid and mucus to be expelled

Pelvic outlet

wider from front to back.

To ensure the adequacy of the pelvic outlet for vaginal birth, the following pelvic measurements are assessed: diagonal conjugate, transverse or ischial tuberosity, and the true or obstetric conjugate

Diagonal conjugate of the inlet

distance between the anterior surface of the sacral prominence and the anterior surface of the inferior margin of the symphysis pubis

measures at least 11.5 cm

Transverse or ischial tuberosity diameter of the outlet

distance at the medial and lowest aspect of the ischial tuberosities, at the level of the anus; a known hand span or clenched-fist measurement is generally used to obtain this measurement

True or obstetric conjugate

distance estimated from the measurement of the diagonal conjugate; 1.5 cm is subtracted from the diagonal conjugate measurement

measures 10 cm or more (1.5 cm less than the diagonal conjugate, or about 10 cm)

The pelvis is divided into four main shapes:

gynecoid, anthropoid, android, and platypelloid

most pelvises are not purely defined but occur in nature as mixed types. Many women have a combination of these four basic pelvis types

Gynecoid pelvis

considered the true female pelvis, 40% of all women, vaginal birth is the most favorable with this shape

offers the optimal diameters in all three planes of the pelvis

most optimal child birth, most common

Anthropoid pelvis

pelvic inlet is oval and the sacrum is long

Vaginal birth is more favorable with this pelvic shape compared to the android or platypelloid shape (so second best shape)

Android pelvis

considered the male-shaped pelvis and is characterized by a funnel shape. pelvic inlet is heart shaped

failure of the fetus to rotate is common.

prognosis for labor is poor, subsequently leading to cesarean birth

Platypelloid (flat) pelvis

least common type of pelvic structure

Labor prognosis is poor with arrest at the inlet occurring frequently. not favorable for a vaginal birth unless the fetal head can pass through the inlet

Soft tissues

The soft tissues of the passageway consist of the cervix, the pelvic floor muscles, and the vagina

soft tissues of the vagina expand to accommodate the fetus during birth.

Passenger is who

The fetus and the placenta are the passengers

aspects that affect the passenger are what

The fetal head (size and presence of molding); fetal attitude (degree of body flexion); fetal lie (relationship of body parts); fetal presentation (first body part); fetal position (relationship to maternal pelvis); fetal station; and fetal engagement are all important factors that have an impact on the ultimate outcome in the birthing process.

This malleability of the fetal skull may decrease fetal skull dimensions by ____-_____ cm

0.5 to 1

Molding

The changed (elongated) shape of the fetal skull at birth as a result of overlapping of the cranial bones

caput succedaneum:

caput succedaneum: fluid can also collect in the scalp causing edema of the scalp at the presenting part

Cephalohematoma:

blood can collect beneath the scalp, generally reabsorbed over the next 6 to 8 weeks

Anterior fontanel

remains open for 12 to 18 months after birth to allow for growth of the brain. Diamond shape

The two most important diameters that can affect the birth process are the

suboccipitobregmatic (approximately 9.5 cm at term) and the biparietal (approximately 9.25 cm at term) diameters.

Posterior fontanel:

closes within 8 to 12 weeks after birth and on average, triangle shape

suboccipitobregmatic diameter, measured from the

base of the occiput to the center of the anterior fontanelle, identifies the smallest anteroposterior diameter of the fetal skull

biparietal diameter measures the

largest transverse diameter of the fetal skull—the distance between the two parietal bones

Fetal altitude

refers to the posturing (flexion or extension) of the joints and the relationship of fetal parts to one another

most common fetal attitude when labor begins is

with all joints flexed—the fetal back is rounded, the chin is on the chest, the thighs are flexed on the abdomen, and the legs are flexed at the knees. This presents the smallest fetal skull diameter and is optimal for birth

Fetal lie

refers to the relationship of the long axis (spine) of the fetus to the long axis (spine) of the mother.

There are three possible lies: longitudinal (the most common), transverse and oblique

A longitudinal lie occurs when

the long axis of the fetus is parallel to that of the mother (fetal spine to maternal spine side-by-side).

A transverse lie occurs when

the long axis of the fetus is perpendicular to the long axis of the mother (fetal spine lies across the maternal abdomen and crosses her spine).

cannot deliver vaginally in the position

An oblique lie

the fetal long axis is at an angle to the bony inlet, and no palpable fetal part is presenting. usually transitory and occurs during fetal conversion between other lies.

Fetal presentation

refers to the body part of the fetus that enters the pelvic inlet first (the "presenting part")

cephalic

breech

shoulder

Cephalic is what presentation

head first

what are the four possible cephalic presentations

vertex

military

brow

face

Vertex

what you want, smallest part of the babies head (optical portion) presents, full flexion with chin to chest

Military

top of the babies head

Brow

extension of the babies neck, can see brows

Face

full extension, babies face is first

Breech presentation

occurs when the fetal buttocks or feet enter the maternal pelvis first and the fetal skull enters last

Frank breech

Complete breech.

Single footling breech

Double footling breech.

frank breech

(50% to 70%), the buttocks present first with both legs extended up toward the face

full or complete breech

(5% to 10%), the fetus sits cross-legged above the cervix

footling or incomplete breech

(10% to 30%), one or both legs are presenting.

Breech presentations are associated with

Breech presentations are associated with prematurity, placenta previa, multiparity, uterine abnormalities (fibroids), and some congenital anomalies such as hydrocephalus

Shoulder presentation

occurs when the fetal shoulders present first with the head tucked inside

signs of shoulder dystocia appear

while the woman is pushing as the neonate's head slowly extends and emerges over the perineum but then retracts back into the vagina, commonly referred to as the "turtle sign."

Conditions associated with shoulder dystocia include

placenta previa, prematurity, high parity, premature rupture of membranes, multiple gestation, or fetal anomalies.

Fetal position

describes the relationship of a given point on the presenting part of the fetus to a designated point of the maternal pelvis

Position is indicated by a three-letter abbreviation as follows:

The first letter defines whether the presenting part is tilted toward the left (L) or the right (R) side of the maternal pelvis.

The second letter represents the particular presenting part of the fetus: O for occiput, S for sacrum, M for mentum, A for acromion process, and D for dorsal (refers to the fetal back) when denoting the fetal position in shoulder presentations.

The third letter defines the location of the presenting part in relation to the anterior (A) portion of the maternal pelvis or the posterior (P) portion of the maternal pelvis. If the presenting part is directed to the side of the maternal pelvis, the fetal presentation is designated as transverse (T).

____ is currently the most common (and most favorable) fetal position for birthing

LOA

followed by ROA as the next most common

LOA and ROA are optimal positions for vaginal birth.

Fetal station

refers to the relationship of the presenting part to the level of the maternal pelvic ischial spines as this is the narrowest part of the pelvic

measured in centimeters and is referred to as a minus or plus, depending on its location above or below the ischial spines (-4 - +4)

Zero (0) station is designated when the presenting part is at the level of the maternal ischial spines

Fetal engagement

signifies the entrance of the largest diameter of the fetal presenting part (usually the fetal head) into the smallest diameter of the maternal pelvis

fetus is said to be engaged in the pelvis when the presenting part reaches 0 station

floating

is a term used when engagement has not occurred because the presenting part is freely movable above the pelvic inlet.

Cardinal movements of labor

positional changes as the fetus travels through the passageway

Descent

the downward movement of the fetal head until it is within the pelvic inlet

occurs throughout labor, ending with birth

Engagement

0 station

flexion

occurs as the vertex meets resistance from the cervix, the walls of the pelvis, or the pelvic floor

internal rotation

head rotates about 45 degrees anteriorly to the midline under the symphysis, after engagement

extension

Resistance from the pelvic floor causes the fetal head to extend so that it can pass under the pubic arch. occurs after internal rotation is complete

External rotation (restitution)

head is born and is free of resistance, it untwists, causing the occiput to move about 45 degrees back to its original left or right position (restitution)

Expulsion

Rest of babies body comes out

Powers

uterine contractions and intra-abdominal pressure (pushing)

Uterine contractions

are rhythmic and intermittent, with a period of relaxation between contractions

effacement

Cervical canal 2 cm in length would be described as 0% effaced.

Cervical canal 1 cm in length would be described as 50% effaced.

Cervical canal 0 cm in length would be described as 100% effaced.

Each contraction has three phases:

increment (buildup of the contraction), acme (peak or highest intensity), and decrement (descent or relaxation of the uterine muscle fibers).

Uterine contractions are monitored and assessed according to three parameters:

frequency, duration, and intensity.

Intra-abdominal pressure

(voluntary muscle contractions) compresses the uterus and adds to the power of the expulsion forces of the uterine contractions

Goal is 3 pushes per contraction, hold breath for 10 seconds and bear down, breath and go again

Position (maternal)

Changing position and walking affect the pelvis joints, which may facilitate fetal descent and rotation.

Psychological response

Having a strong sense of self and meaningful support from others can often help women manage labor well.

Philosophy

Physiologic childbirth is an approach to care that supports the body's ability to perform processes during childbirth while considering the woman's philosophy, values, and preferences during this life event.

Partners

Partner can be anyone who is present to support the woman throughout the experience

Nursing care of women during labor should incorporate finding a way to connect with her and to understand what she is experiencing (knowing); spending time with her (presence); protecting her and preserving her dignity (doing for); providing information and explanations in a clear methodical manner (enabling); and ensuring a safe childbirth experience.

Induction of labor

Approximately one in four women (24%) are induced or have labor augmented with uterine-stimulating drugs or artificial rupture of membranes to accelerate progress and early-term (in the 37th and 38th week) inductions