Chapter 13 Labor & Birth Process

Question 1

Initiation of Labor

Answer 1

It is difficult to determine exactly why labor begins & what initiates it

Question 2

It is widely believed that labor is influenced by a cascade of events, such as…

Answer 2

…uterine stretch from the fetus and amniotic fluid volume, progesterone withdrawal to estrogen dominance, increased oxytocin sensitivity, & increased prostaglandin release

Question 3

Theories of Labor

Answer 3

Uterine distention, increasing uterine pressure

Aging of the placenta

Increased sensitivity to Oxytocin

Changes in barometric pressure

Changes in hormonal concentration:
- Estrogen increase
- Progesterone decreases

Question 4

What is the influence of prostaglandins on the initiation of labor?

Answer 4

Additional contractions
Cervical softening
Gap junction induction
Myometrial sensitization
- Leads to cervical dilation

Question 5

Cervical Dilation

Answer 5

The opening/enlargement of the cervical os

Question 6

What are two functions of contractions?

Answer 6

1) Dilate the cervix
2) Push the fetus through the birth canal

Question 7

Cervical Changes During Labor

Answer 7

Before labor begins, cervical softening (ripening) & possible cervical dilation w/descent of the presenting part into the pelvis occur
- These changes can occur 1 month- 1hr before actual labor begins

As labor approaches: elongated structure-> shortened, thinned segment

These changes occur secondary to prostaglandin effect & Braxton Hicks contractions

These changes are VITAL for cervical dilation & effacement

Question 8

Lightening

Answer 8

Fetus descends into the pelvic inlet (engagement)

Breathing is much easier & decrease in gastric refles

Pressure is then moved from the pressing up against
the diaphragm to the lower abdominal
area causing:
- Leg cramps
- Increased pelvic pressure
- Venous stasis
- Urinary frequency
- Increased vaginal secretions

In primiparas, lightening can occur 2 weeks or more before labor begins
- Multiparas: May not occur until labor starts

Question 9

Increased Energy Levels

Answer 9

Some women may report sudden boost in energy levels
- “Nesting”: Childbirth prep via cooking, cleaning, prepping the nursery, & spending more time w/ other children

Question 10

Bloody Show

Answer 10

Cervical secretions mixed w/ some blood from ruptured capillaries; mucus plug is expelled

Question 11

Braxton Hicks

Answer 11

Irregular, intermittent contractions, may become
uncomfortable (false labor)
- Usually last 30 secs but can last up to 2 mins

Experienced throughout pregnancy & become stronger as due date approaches

Tightening/pulling sensation felt at the top of the uterus
- Occur primarily in the abdomen & groin and gradually spread down ward before relaxing

Functions:
- Aid in moving the cervix from posterior-> anterior position
- Aid in softening & ripening of the cervix

Alleviated by:
- Walking
- Voiding
- Eating
- Increasing fluid intake
- Changing position

Question 12

If contractions last more than 30 secs & occur more than 4-6X an hr…

Answer 12

… advise the woman to call her health provider to be evaluated for possible preterm labor, especially if < 38 weeks pregnant

Infant born 34 0/7 – 36 6/7 weeks are “late preterm”
- May experience same health issues like other premature infants

Question 13

Rupture of Membranes

Answer 13

PROM (prelabor rupture of membranes): The rupture of membranes w/ amniotic fluid loss prior to onset of labor
- Occurs in 8-10% of women w/term pregnancies

Can result as either a sudden gush or steady stream of fluid
- Although much of the amniotic fluid is lost, still continuous supply is ensured to protect the fetus until birth

Barrier to infection is gone & ascending infection is possible

Risk of cord prolapse if engagement has not occurred w/ release of fluid & pressure w/ rupture
- Advise women to notify their health providers & go in for eval

Question 14

True Labor

Answer 14

Contraction Timing: Regular, becoming close together, usually 4-6 mins apart, lasts 30-60 secs

Contraction Strength: Become stronger w/time, vaginal pressure is usually felt

Contraction Discomfort: Starts in the back & radiates around toward the front of the abdomen

Any change in activity: Contractions continue no matter what positional change is made

Stay or Go?
Stay until contractions are 5 mins apart & last 45-60 secs, & strong enough that a conversation during this is not possible
-> Then go to the hospital or birthing center

Question 15

False Labor

Answer 15

Contraction Timing: Irregular, not close together

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

Contraction Discomfort: Usually felt in the front of the abdomen

Any change in activity: Contractions may stop or slow down with walking or making a position change

Stay or Go? : 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.

Question 16

In order to be considered a true labor, what are the 2 requirements?

Answer 16

Cervical dilation & regular contractions

Question 17

Factors that Affect the Labor Process

Answer 17

AKA “The 5 P’s”

1) Passageway (birth canal)

2) Passenger (fetus and placenta)

3) Powers (contractions)

4) Position (maternal)

5) Psychological response

Question 18

The 5 P’s of Caring for the Family

Answer 18

1) Philosophy (low-tech, high-touch)

2) Partners (support caregivers)

3) Patience (natural timing)

4) Patient (client) preparation (childbirth knowledge base)

5) Pain management (comfort measures)

Question 19

Birth Passageway

Answer 19

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

Question 20

False (Greater) Pelvis

Answer 20

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: The false pelvis is divided from the true pelvis by 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
- The false pelvis lies above this imaginary line; the true pelvis lies below it

Question 21

True Pelvis

Answer 21

The bony passageway through which the fetus must travel.

It is made up of three planes: the inlet, the mid-pelvis (cavity), and the outlet.

Question 22

What are the 4 pelvis shapes?

Answer 22

1) Gynecoid
2) Anthropoid
3) Android
4) Platypelloid

Question 23

Gynecoid

Answer 23

Considered the true female pelvis, occurring in about 40% of all women
- Less common in men

Vaginal birth is most favorable with this type of pelvis because the inlet is round and the outlet is roomy

This shape offers the optimal diameters in all three planes of the pelvis

Allows early and complete fetal internal rotation during labor.

Question 24

Anthropoid

Answer 24

Common in men and is most common in non-White women.

It occurs in approximately 25% of women

The pelvic inlet is oval and the sacrum is long, producing a deep pelvis (wider front to back [anterior to posterior] than side to side [transverse]).

Vaginal birth is more favorable with this pelvic shape compared to the android or platypelloid shape

Question 25

Android

Answer 25

Considered the male-shaped pelvis and is characterized by a funnel shape

Occurs in approximately 20% of women

The pelvic inlet is heart shaped & the posterior segments are reduced in all pelvic planes

Descent of the fetal head into the pelvis is slow, and failure of the fetus to rotate is common

Prognosis for Labor: Poor, subsequently leading to cesarean birth

Question 26

Platypelloid

Answer 26

AKA “Flat Pelvis”

Least common type of pelvic structure among men and women with an approximate incidence of 3%

Pelvic cavity is shallow but widens at the pelvic outlet, making it difficult for the fetus to descend through the mid-pelvis

Labor prognosis: Poor with arrest at the inlet occurring frequently

NOT favorable for a vaginal birth unless the fetal head can pass through the inlet

Women with this type of pelvis usually require cesarean birth.

Question 27

Soft Tissue Changes

Answer 27

Components: Cervix, pelvic floor muscles, & vagina

The pelvic floor muscles help the fetus rotate anteriorly as it passes through the birth canal

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

Question 28

Effacement

Answer 28

Cervix is thinning to allow the presenting part of the fetus to descend into the vagina

Measured as a Percentage 0% to100%
- 100% is complete

A cervix of a non-laboring patient is usually long and thick

Question 29

Fetal Head

Answer 29

Largest fetal structure

The bones that make up the face and cranial base are fused and essentially fixed
- The 5 bones that make up the rest of the cranium (2 frontal bones, 2 parietal bones, & the occipital bone) are not fused
- Skull is soft & pliable

Sutures: Gaps between the plates of bone
- Allow the cranial bones to overlap in order for the head to adjust in shape (elongate) when pressure is exerted on it by uterine contractions or the maternal bony pelvis
- After birth, the sutures close as the bones grow and the brain reaches its full growth

Fontanelles: Intersections of the sutures
- 2 fontanelles: Anterior & Posterior

Question 30

Molding

Answer 30

An abnormal head shape that results from pressure on the baby’s head during childbirth

Question 31

Anterior Fontanelle

Answer 31

AKA “Soft Spot”

A diamond-shaped space that measures from 1 to 4 cm

Remains open for 12–18 months after birth to allow for growth of the brain

Question 32

Posterior Fontanelle

Answer 32

Located at the back of the fetal head

Triangular-shaped

Closes w/in 8–12 weeks after birth and on average, measures 1 to 2 cm at its widest diameter

Question 33

Fetal Attitude

Answer 33

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

Most common: 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 knee
- Most favorable for vaginal birth-> presenting the smallest fetal skull diameters to the pelvis

Question 34

Fetal Lie

Answer 34

Refers to the relationship of the long axis (spine) of the fetus to the long axis (spine) of the mother

Question 35

What are the 3 possible lies?

Answer 35

1) Longitudinal (most common)
2) Transverse
3) Oblique

Question 36

Longitudinal Lie

Answer 36

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

Question 37

Transverse Lie

Answer 37

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)

Question 38

Oblique Lie

Answer 38

The fetal long axis is at an angle to the bony inlet, and no palpable fetal part is presenting

This lie is usually transitory and occurs during fetal conversion between other lies

Question 39

(T/F) True or False: A fetus in a transverse or oblique lie position cannot be delivered vaginally

Answer 39

True

Question 40

Fetal Presentation

Answer 40

Refers to the body part of the fetus that enters the pelvic inlet first (the “presenting part”)

Question 41

What are the 3 main presentations?

Answer 41

1) Cephalic (head 1st)
2) Breech (pelvis 1st)
3) Shoulder (scapula 1st)

Question 42

Vertex Presentation

Answer 42

Occipital portion of the head presents 1st

Question 43

Breech Presentation

Answer 43

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

Challenges:
- The largest part of the fetus (skull) is born last and may become stuck in the pelvis
- Umbilical cord can become compressed between the fetal skull and the maternal pelvis after the fetal chest is born because the head is the last to exit
- Buttocks are soft and are not as effective as a cervical dilator during labor compared w/ cephalic presentation
-There is the possibility of trauma to the head as a result of the lack of opportunity for molding

Question 44

What are the different types of breech presentation?

Answer 44

1) Frank Breech
2) Complete Breech
3) Single footling breech
4) Double footling breech

Question 45

Frank Breech

Answer 45

Buttocks present 1st w/ both legs extended up toward the face

Question 46

Complete Breech

Answer 46

Fetus sits cross-legged above the cervix

Question 47

Single Footling Breech

Answer 47

1 leg presents 1st

Question 48

Double Footling Breech

Answer 48

2 legs present 1st

Question 49

What are breech positions associated with?

Answer 49

Prematurity
Placenta previa
Multiparity
Uterine abnormalities (fibroids)
Some congenital anomalies such as hydrocephaly

Question 50

Which breech position can result in a vaginal birth?

Answer 50

Frank breech position

Question 51

Shoulder Presentation

Answer 51

AKA “Shoulder Dystocia”

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

Turtle Sign

Occurs 1/300 births

Fetal Lie & Presentation: Transverse lie w/ shoulder presenting

Associated Conditions:
- Placenta previa
- Prematurity
- High parity
- Premature rupture of membranes
- Multiple gestation
- Fetal anomalies

Question 52

Fetal Position

Answer 52

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