Chapter 13 Labor & Birth Process Flashcards
1) Identify premonitory signs of labor 2) Compare & contrast true vs false labor 3) Categorize the critical factors affecting labor & birth 4) Analyze the cardinal moments of labor 5) Evaluate the maternal & fetal responses to labor & birth 6) Examine the concept of pain as it relates to the woman in labor 7) Classify the stages of labor & the critical events in each stage 8) Characterize the normal physiologic/psychological changes occurring during all four stages of labor
Initiation of Labor
It is difficult to determine exactly why labor begins & what initiates it
It is widely believed that labor is influenced by a cascade of events, such as…
…uterine stretch from the fetus and amniotic fluid volume, progesterone withdrawal to estrogen dominance, increased oxytocin sensitivity, & increased prostaglandin release
Theories of Labor
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
What is the influence of prostaglandins on the initiation of labor?
Additional contractions
Cervical softening
Gap junction induction
Myometrial sensitization
- Leads to cervical dilation
Cervical Dilation
The opening/enlargement of the cervical os
What are two functions of contractions?
1) Dilate the cervix
2) Push the fetus through the birth canal
Cervical Changes During Labor
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
Lightening
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
Increased Energy Levels
Some women may report sudden boost in energy levels
- “Nesting”: Childbirth prep via cooking, cleaning, prepping the nursery, & spending more time w/ other children
Bloody Show
Cervical secretions mixed w/ some blood from ruptured capillaries; mucus plug is expelled
Braxton Hicks
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
If contractions last more than 30 secs & occur more than 4-6X an hr…
… 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
Rupture of Membranes
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
True Labor
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
False Labor
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.
In order to be considered a true labor, what are the 2 requirements?
Cervical dilation & regular contractions
Factors that Affect the Labor Process
AKA “The 5 P’s”
1) Passageway (birth canal)
2) Passenger (fetus and placenta)
3) Powers (contractions)
4) Position (maternal)
5) Psychological response
The 5 P’s of Caring for the Family
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)
Birth Passageway
The route through which the fetus must travel to be born vaginally
False (Greater) Pelvis
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
True Pelvis
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.
What are the 4 pelvis shapes?
1) Gynecoid
2) Anthropoid
3) Android
4) Platypelloid
Gynecoid
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.
Anthropoid
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
Android
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
Platypelloid
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.
Soft Tissue Changes
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
Effacement
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
Fetal Head
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
Molding
An abnormal head shape that results from pressure on the baby’s head during childbirth
Anterior Fontanelle
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
Posterior Fontanelle
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
Fetal Attitude
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
Fetal Lie
Refers to the relationship of the long axis (spine) of the fetus to the long axis (spine) of the mother
What are the 3 possible lies?
1) Longitudinal (most common)
2) Transverse
3) Oblique
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)
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)
Oblique Lie
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
(T/F) True or False: A fetus in a transverse or oblique lie position cannot be delivered vaginally
True
Fetal Presentation
Refers to the body part of the fetus that enters the pelvic inlet first (the “presenting part”)
What are the 3 main presentations?
1) Cephalic (head 1st)
2) Breech (pelvis 1st)
3) Shoulder (scapula 1st)
Vertex Presentation
Occipital portion of the head presents 1st
Breech Presentation
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
What are the different types of breech presentation?
1) Frank Breech
2) Complete Breech
3) Single footling breech
4) Double footling breech
Frank Breech
Buttocks present 1st w/ both legs extended up toward the face
Complete Breech
Fetus sits cross-legged above the cervix
Single Footling Breech
1 leg presents 1st
Double Footling Breech
2 legs present 1st
What are breech positions associated with?
Prematurity
Placenta previa
Multiparity
Uterine abnormalities (fibroids)
Some congenital anomalies such as hydrocephaly
Which breech position can result in a vaginal birth?
Frank breech position
Shoulder Presentation
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
Fetal Position
Describes the relationship of a given point on the presenting part of the fetus to a designated point of the maternal pelvis
