Chapter 13 Labor And Birth Process Flashcards Preview

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Flashcards in Chapter 13 Labor And Birth Process Deck (37):

Four things for labor to start

Uterine stretch, progesterone withdrawal, increased oxytocin sensitivity, and increased release of prostaglandins


Cervical changes

Softening, possible dilation with descent.



Fetal presenting part begins to descend into the pelvis. The women usually has easier breathing but may also have increased pelvic pressure, cramping, low back pain, increased vaginal discharge and more frequent urination.


Braxton Hicks contractions

Contractions that are felt as a tightening or pulling on top of the uterus. They occur in the abdomen and growing and gradually spread downward. They are irregular, can be decreased by Walking, voiding, eating, increased fluid intake, or changing position.


Late preterm

Born between 34 and 36 completed weeks of gestation.


Spontaneous rupture of membranes

Barrier to infection is gone, ascending infection is possible, danger of cord prolapse if engagement has not occurred, sudden release of fluid and pressure with rupture.


False labor

Irregular, far apart contractions. Weak contractions that do not get stronger. Felt in front of the abdomen. They may stop or slowdown with walking or position change. Should drink fluids and walk around. If the contractions diminish in intensity they can stay home.


True labor

Contractions become closer together, usually 4 to 6 minutes apart and lasting 30 to 60 seconds. It becomes stronger with time. Start in the back and radiate towards the front of the abdomen. They continues no matter what position change is made. Stay home until contractions are five minutes apart, last 45 to 60 seconds, and are strong enough so that you cannot have a conversation.


Five P's of the labor process

Passageway/birth canal
Passenger/fetus and placenta
Psychological response


Five additional P's of the labor Process

Philosophy/low-tech, high touch
Partners/support caregivers
Patience/natural timing
Patient preparation/childbirth knowledge base
Pain management/comfort measures


False pelvis or greater pelvis

Upper flared parts of the two iliac bones and the wings at the base of the sacrum. It 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 line is called Linnaea terminalis


True pelvis

Lies below the Linea terminalis. Bony passageway through which the fetus must travel. Inlet, cavity, and outlet


Gynecoid pelvis

Vaginal birth is most favorable with this pelvis because the inlet is round and the outlet is roomy. This type of pelvis allows early and complete fetal internal rotation during labor


Anthropoid pelvis

Occurs in 25% of women. Inlet is oval and the sacrum is long, producing a deep pelvis. Second most favorable pelvis.


Android pelvis

Male shaped pelvis that occurs in 20% of women. Inlet is heart-shaped the posterior segments are reduced. Descent of the fetal head into the pelvis is slow and failure of the fetus to rotate is common. Prognosis for labor is poor leading to C-section


Platypelloid or flat pelvis

Least common and occurs 5%. Pelvic cavity is shallow but widens at the pelvic outlet, making it difficult for the fetus to descend through mid pelvis. Labor prognosis is poor. Not favorable for a vaginal birth unless the fetal head can pass through the inlet. They usually require a C-section.



The cervix thins and allows the presenting fetal part to descend into the vagina. Similar to that of pulling a turtleneck sweater over your head


Fetal head

The largest and least compressible fetal structure. Sutures allow the cranial bones to overlap in order for the head to adjust in shape, this is known as molding. Palpation of the sutures help identify the position of the fetal head. The anterior and posterior fontanelles also help identify position and allow for molding. The anterior is diamond shape, the posterior is triangular. The anterior remains open for 12 to 18 months. The posterior closes within 8 to 12 weeks.


Fetal attitude

The flexion or extension of the joints and the relationship of fetal parts to one another. Most common begins with all joints flexed. Back is rounded, chin on chest, size legs are are flexed. Most favorable for vaginal birth.


Fetal lie

Long axis spine of the fetus to the long axis spine of the mother. Longitudinal most common and transverse. Longitudinal occurs when the fetus is parallel to that of the mother. Transverse is perpendicular and cannot be delivered vaginally


Fetal presentation

The part of the body that enters the pelvic inlet inlet first. Three main fetal presentations are cephalic headfirst, breach pelvis first, and shoulder scapula first.


Cephalic presentation

Occiput portion of the fetal head is first.


Breech presentation

Frank breech is 50 to 70%, the butt presents first with both legs towards the face.

Full or complete breach is 5 to 10%, fetus is crosslegged above the cervix.

Footling or incomplete breach occurs 10 to 30%, one or both legs are presenting

Frank breech can deliver vaginally but complete, footling, and incomplete need a C-section


Shoulder presentation

One in 300 births. Must assess for fetal anomalies. Associated with placenta previa, prematurity, high parity, premature rupture of membranes, multiple gestation, or fetal anomalies. A C-section is usually necessary before labor begins


Fetal station

The presenting part the level of the maternal pelvic ischial spines. Zero station the fetus is said to be engaged. Negative it can still move up and down (floating). +1 to +4 when the fetus is descending downward.


Cardinal movements of labor

1. Engagement when the head passes through the pelvic inlet at zero station
2. Descent is downward movement of the fetal head into the pelvic inlet that is brought on by pressure of the amnionic fluid, direct pressure of the fundus, contractions, extension and straightening of the body
3. Flexion is when the chin is brought into the chest
4. Internal rotation aligns the long axis of the fetal head with the long axis of the pelvis
5. Extension occurs after internal rotation is complete the head emerges through the symphysis pubis along with the shoulders
6. External rotation/restitution after the head is born it twists causing the occipital to move about 45°. Allows the shoulders to rotate to fit the pelvis
7. Expulsion the rest of the body is birthed


Uterine contractions

Involuntary, responsible for thinning and dilating the cervix, thrust the presenting part or the lower uterine segment. They are monitored according to frequency, duration, and intensity.



Thinning of the cervical canal reduces in length
2 cm in length would be 0% effaced
1 cm 50%
0 cm 100%



Diameter of the cervical OS increases from less than 1 cm to approximately 10 cm


Maternal responses to labor

Heart rate increases 10 to 20 beats
Cardiac output increases
Blood pressure increases during contractions
White blood cell count increases to 25 to 30,000
Respiratory rate increases more oxygen and increases metabolism
Gastric motility and food absorption decrease resulting in nausea and vomiting during transition
Gastric emptying and gastric pH decrease
Increase in temperature
Muscular aches and cramps
Basal metabolic rate increases blood glucose levels decrease


Fetal responses to labor

Periodic heart rate acceleration and slight decelerations related to fetal movement, fundal pressure, and uterine contraction

Decrease in circulation and perfusion to the fetus

Increase in arterial CO2
Decrease in fetal breathing movements
Decrease in fetal oxygen pressure with decrease in PO2
* Respiratory changes during labor help to prepare the fetus for extrauterine respiration immediately after birth


Placental separation

The following signs indicate the placenta is ready to deliver. The uterus rises upward. Umbilical cord lengthens. A sudden trickle of blood is released from the vaginal opening. The uterus changes it's shape to globular.


Increase in prostaglandin levels

Causes myometrial contractions leading to a reduction in cervical resistance and softening and thinning of the cervix.


Caput succedaneum

Fluid collects in the scalp. Edema of the scalp at the presenting part. The swelling crosses suture lines. Usually disappears within 3 to 4 days.



Blood collects beneath the scalp. Is a collection of blood between the periosteum and the bone that occurs several hours after birth. It does not cross suture lines, and is reabsorbed over the next 6 to 8 weeks


Powers of labor

The primary stimulus powering labor is uterine contractions which are responsible for dilation and effacement

Secondary power of labor is the use of abdominal pressure/voluntary muscle contractions during pushing.


Phases and stages of labor

Stage one: the latent phase (0-3cm), active phase (4-7cm), transition phase (8-10). From 0 to 10 cm dilation, consists of three phases.

Stage II: pelvic phase, Perineal phase. From complete dilation to birth of the new born. Up to three hours

Stage III: Placental separation, placental expulsion. Separation and delivery of the placenta takes 5 to 10 minutes but up to 30

Stage 4: 1 to 4 hours after birth