OB Chapter 13: Labor and Birth Process

Flexion

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

False labor

occurs during the latter weeks of some pregnancies in which irregular uterine contractions are felt, but the cervix is not affected.

phases of second stage of labor ( 2)

pelvic and perineal

anthropoid pelvis

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 an-droid or platypelloid shape

Conditions associated with shoulder dystocia

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

Stage Three

placental expulsion, starts after the newborn is born and ends with the separation and birth of the placenta.

Phases of Stage three (2)

placental separation and placental expulsion

Complication of breech presentations

prematurity, placenta previa, multiparity, uterine abnormalities (broids), and some congenital anomalies such as hydrocephaly

contractions

primary stimulus powering labor

Fetal presentation

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

Fetal attitude

refers to the posturing (flexion or extension) of the joints and the relationship of fetal parts to one another. The 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 (An attitude of extension tends to present larger fetal skull diameters, which may make birth diffcult.)

Stage Four

restorative stage or immediate postpartum period, lasts from 1 to 4 hours -begins with completion of the expulsion of the placenta and membranes and ends with the initial physiologic adjustment and stabilization of the mother focus is to monitor the mother closely to prevent hemorrhage, bladder distention, and venous thrombosis q 15 mins monitoring

maternal pelvis is divided into four quadrants:

right anterior, left anterior, right posterior, and left posterior.

Increased energy level

some women report a sudden increase in energy before labor. This is sometimes referred to as nesting, because many women will focus this energy toward child-birth preparation by cleaning, cooking, preparing the nursery, and spending extra time with other children in the household. The increased energy level usually occurs 24 to 48 hours before the onset of labor. It is thought to be the result of an increase in epinephrine release caused by a decrease in progesterone

nucha

the base of the occiput

effacement

the cervix effaces (thins)

Descent

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

Fetal engagement

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.

Schultz's mechanism

the fetal side (shiny gray side) of placenta presenting

family-centered birthing

the low-tech, high-touch approach requested by many childbearing women, who view childbirth as a normal process.

passageway

the maternal pelvis and soft tissues.

Bloody Show

the mucous plug that fills the cervical canal during pregnancy is expelled (ruptured cervical capillaries release a small amount of blood that mixes with mucus,)

dilation

the opening or enlargement of the external cervical os

Fetal position describes

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

Fetal lie

the relationship of the long axis (spine) of the fetus to the long axis (spine) of the mother. -two primary lies: longitudinal (which is the most common) and transverse

secondary powers in labor

the use of intra-abdominal pressure (voluntary muscle contractions) exerted by the woman as she pushes and bears down during the second stage of labor.

Bony Pelvis

true +false portions: The false (or greater) pelvis is composed of the upper flared parts of the two iliac bones The true pelvis is 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.

floating

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

Lightening

when the fetal presenting part begins to descend into the maternal pelvis

shoulder presentation or shoulder dystocia

when the fetal shoulders present first, with the head tucked inside/ fetus is in a transverse lie with the shoulder as the presenting part.

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

when the long axis of the fetus is perpendicular to the long axis of the mother (fetus spine lies across the maternal abdomen and crosses her spine). A fetus in a transverse lie position cannot be delivered vaginally

phases of contractions (3)

increment (buildup of the contraction), acme (peak or highest in-tensity), and decrement (descent or relaxation of the uterine muscle fibers;

Doula

is a Greek word meaning "woman ser-vant" or "caregiver." It now commonly refers to a woman who offers emotional and practical support to a mother or couple before, during and after childbirth.

sagittal suture

is located between the parietal bones and divides the skull into the right and left halves.

Initiation of labor

labor is initiated by a change in the estrogen-to-progesterone ratio.

Phases of the first stage (3)

latent or early phase, active phase, and transition phase.

posterior fontanelle

located at the back of the fetal head; it is triangular. This one closes within 8 to 12 weeks after birth and measures, on average, 1 to 2 cm at its widest diameter

Coronal suture

located between the frontal and parietal bones and extend transversely on both sides of the anterior fontanelles.

lambdoidal sutures

located between the occipital bone and the two parietals, ex-tending transversely on either side of the posterior fonta-nelles.

frontal suture

located between the two frontal bones.

Duncan's mechanism

maternal side of placenta presenting

Factors promoting a positive birth experience

Clear information about procedures Support; not being alone Sense of mastery, self-condence Trust in staff caring for her Positive reaction to the pregnancy Personal control over breathing Preparation for the childbirth experience

Signs that the placenta is ready to deliver:

The uterus rises upward. The umbilical cord lengthens. A sudden trickle of blood is released from the vaginal opening. The uterus changes its shape to globular.

anterior fontanelle

"soft spot" of the newborn's head. It is a diamond-shaped space that measures from 1 to 4 cm. It remains open for 12 to 18 months after birth to allow for growth of the brain

suboccipitobregmatic

(9.5 cm), which achieves the smallest fetal skull diameter presenting to the maternal pelvic dimensions.

Pelvic shapes (4)

(A) Gynecoid. (B) Android. (C) Anthro-poid. (D) Platypelloid.

Fetal presentation: cephalic presentations (4)

(A) Vertex. (B) Military. (C) Brow. (D) Face.

lochia

(vaginal discharge) is red, mixed with small clots, and of moderate flow

Cesarean birth

-associated with increased morbidity and mortality for both mother and infant, as well as increased inpatient length of stay and health care costs -32.8%

caput succedaneum

-fluid collection in the scalp/ edema of the scalp at the presenting part. -swelling crosses suture lines and disappears within 3 to 4 days

First Stage

-it begins with the first true contraction and ends with full dilation (opening) of the cervix- -LONGEST -ends when the cervix is dilated to 10 cm -fetal membranes, or bag of waters, usually rupture

platypelloid or flat pelvis

-least common type pelvic cavity is shallow but widens at the pelvic out-let, making it difficult for the fetus to descend through the mid-pelvis. Labor prognosis is poor

Fetal station

-refers to the relationship of the presenting part to the level of the maternal pelvic ischial spines -measured in centimeters and is referred to as a minus or plus - the closer the presenting part of the fetus is to the out-side, the larger the positive number (+4 cm)

Uterine contractions

-rhythmic, intermittent and involuntary -thin and dilate the cervix -thrust the presenting part toward the lower uterine segment.

internal rotation.

-the head rotates about 45 degrees anteriorly to the midline under the symphysis. -brings the anteroposterior diam-eter of the head in line with the anteroposterior diameter of the pelvic outlet. It aligns the long axis of the fetal head with the long axis of the maternal pelvis.

Braxton Hicks Contractions

-typically felt as a tightening or pulling sensation of the top of the uterus. -Aid in moving the cervix from a posterior position to an anterior position and in ripening and softening the cervix. -30 seconds -2 minutes

Cardinal Movements of Labor (3)

1. Engagement 2. Descent 3. Flexion

Factors that affect the process of labor and birth - the 5 P's

1. Passageway (birth canal) 2. Passenger (fetus and placenta) 3. Powers (contractions) 4. Position (maternal) 5. Psychological response

Position is indicated by a three-letter abbreviation .

1. The first letter defines whether the presenting part is tilted toward the left (L) or the right (R) side of the maternal pelvis 2.The second letter represents the particular presenting part of the fetus: O for occiput, S for sacrum (buttocks), M for mentum (chin), A for acromion process, and D for dorsal (refers to the fetal back) when denoting the fetal position in shoulder presentations 3. 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). LOA is the most common (and most favorable) fetal position for birthing today, followed by right occiput anterior (ROA).

additional "P's" can also affect the labor process

: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)

Types of breech presentations

A. Frank breech- the buttocks present first with both legs extended up toward the face. (can be vag delivery) B. full or complete breech - the fetus sits crossed-legged above the cervix. (C section needed) C. Footling or incomplete breech, one or both legs are presenting.(C section needed)

Maternal physiologic responses

A. Heart rate increases by 10 to 20 bpm. B. Cardiac output increases by 12% to 31% during the first stage of labor and by 50% during the second stage of labor. C. Blood pressure increases by up to 35 mm Hg during uterine contractions in all labor stages. D. The white blood cell count increases to 25,000 to 30,000 cells/mm3, perhaps as a result of tissue trauma. E. Respiratory rate increases and more oxygen is consumed related to the increase in metabolism. F. Gastric motility and food absorption decrease, which may increase the risk of nausea and vomiting during the transition stage of labor. G. Gastric emptying and gastric pH decrease, increasing the risk of vomiting with aspiration. H. Temperature rises slightly, possibly due to an increase in muscle activity. I. Muscular aches/cramps occur as a result of the stressed musculoskeletal system. J. Basal metabolic rate increases and blood glucose levels decrease because of the stress of labor

fetal physiologic adaptations

A. Periodic fetal heart rate accelerations and slight decel-erations related to fetal movement, fundal pressure, and uterine contractions B. Decrease in circulation and perfusion to the fetus sec-ondary to uterine contractions (a healthy fetus is able to compensate for this drop) C. Increase in arterial carbon dioxide pressure (PCO2) D. Decrease in fetal breathing movements throughout labor E. Decrease in fetal oxygen pressure with a decrease in the partial pressure of oxygen (PO2)

Factors that affect maternal coping ability

A. Previous birth experiences and their outcomes (com-plications and previous birth outcomes) B. Current pregnancy experience (planned versus un-planned, discomforts experienced, age, risk status of pregnancy, chronic illness, weight gain) C. Cultural considerations (values and beliefs about health status) D. Support system (presence and support of a valued partner during labor) E. Childbirth preparation (attended childbirth classes and has practiced paced breathing techniques) F. Exercise during pregnancy (muscles toned; ability to assist with intra-abdominal pushing) G. Expectations of the birthing experience (viewed as a meaningful or stressful event) H. Anxiety level (excessive anxiety may interfere with la-bor progress) I. Fear of labor and loss of control (fear may enhance pain perception, augmenting fear) J. Fatigue and weariness (not up for the challenge/duration of labor)

restitution

After the head is born and is free of resistance, it un-twists, causing the occiput to move about 45 degrees back to its original left or right position - allows the shoulders to rotate internally to fit the maternal pelvis.

maternal features during the transitional phase

nausea and vomiting, trembling extrem-ities, backache, increased apprehension and irritabil-ity, restless movement, increased bloody show from the vagina, inability to relax, diaphoresis, feelings of loss of control, and being overwhelmed (I can't take it anymore")

cervical softening

Before labor begins, cervical softening and possible cer-vical dilation with descent of the presenting part into the pelvis occur. These changes can occur 1 month to 1 hour before actual labor begins.

Evidence-based practice focuses on a physiologic approach to the second stage of labor. .

Behaviors demonstrated by laboring women during this time include pushing at the onset of the urge to bear down; using their own pattern and technique of bearing down in re-sponse to sensations they experience; using open-glottis bearing down with contractions; pushing with variations in strength and duration; pushing down with progres-sive intensity; and using multiple positions to increase progress and comfort

Engagement

Engagement occurs when the greatest transverse diameter of the head in vertex (biparietal diameter) passes through the pelvic inlet (usually 0 station)

extention

Resistance from the pelvic floor causes the fetal head to extend so that it can pass under the pubic arch

biparietal diameter

The largest diameter of the fetal head

mid-pelvis (cavity)

occupies the space between the inlet and outlet. (s the fetus passes through this small area, its chest is compressed, causing lung fluid and mucus to be expelled)

molding

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

Passenger

The fetus (with placenta)

Spontaneous Rupture of Membranes

a sudden gush or a steady leak-age of amniotic fluid. -ascending infection is now possible. -there is a danger of cord prolapse

pelvic inlet

allows entrance to the true pelvis.

Normal blood loss

approximately 500 mL for a vaginal birth and 1,000 mL for a cesarean birth

amniotomy

artificial rupture of the fetal membranes performed to augment or induce labor when the membranes have not ruptured spontaneously

pelvic outlet

bound by the ischial tuberosities, the lower rim of the symphysis pubis, and the tip of the coccyx.

main fetal presentations (3)

cephalic (head first) breech (pelvis first) shoulder (scapula first)

premonitory signs and symptoms of labor (6)

cervical changes, lightening, increased energy level, bloody show, braxton hicks, spontaneous rupture of membranes

Soft tissues of the passageway (3)

cervix, the pelvic floor muscles, and the vagina.

cephalohematoma

collection of blood between the periosteum and the bone that occurs several hours after birth. It does not cross suture lines and is generally reabsorbed over the next 6 to 8 weeks

android pelvis

considered the male-shaped pelvis and is characterized by a funnel shape. prognosis for labor is poor

gynecoid pelvis

considered the true female pelvis 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. This type of pelvis allows early and complete fetal internal rotation during labor.

true labor

contractions occurring at regular intervals that increase in frequency, duration, and intensity and bring about progressive cervical dilation and effacement.

three phases:contraction has

increment (buildup of the contraction), acme (peak or highest in-tensity), and decrement (descent or relaxation of the uterine muscle bers;

stages of labor (4)

dilation, expulsive, placental, and restorative.

Stage Two

expulsive stage, The second stage of labor begins with complete cervical dilation (10 cm) and effacement and ends with the birth of the newborn. - pushing

Uterine contractions are monitored and assessed according to parameters: (3)

frequency, duration, and intensity. Frequency: refers to how often the contractions occur and is measured from the beginning of one contraction to the beginning of the next contraction Duration: refers to how long a contraction lasts and is measured from the beginning of one contraction to the end of that same contraction. Intensity refers to the strength of the contraction deter-mined by manual palpation or measured by an internal intrauterine pressure catheter.