MODULE 2 LESSON 2 - the process of labor and birth

Passageway-Passenger Relationship

The relationship between the maternal pelvis and the fetus that affects the progress of labor.

Passageway

The maternal pelvis through which the fetus passes during birth.

Passenger

The fetus and fetal membranes.

Engagement

Occurs when the widest diameter of the fetal presenting part passes through the pelvic inlet.

Engagement in Primigravidas

Usually occurs about 2 weeks before the expected due date.

Station

The level of the fetal presenting part in relation to the maternal ischial spines.

Ischial Spines

Bony landmarks of the maternal pelvis used as the reference point for fetal station.

Position

The location of a fixed reference point on the fetal presenting part relative to a quadrant of the maternal pelvis.

Maternal Pelvic Quadrants

• Right anterior

• left anterior

• right posterior

• left posterior.

Right Anterior (RA)

The fetal landmark is directed toward the mother's right front.

Left Anterior (LA)

The fetal landmark is directed toward the mother's left front.

Right Posterior (RP)

The fetal landmark is directed toward the mother's right back.

Left Posterior (LP)

The fetal landmark is directed toward the mother's left back.

Fetal Presentation

The part of the fetus that overlies the maternal pelvis.

Fetal Lie

The relationship between the longitudinal axis of the fetus and the longitudinal axis of the mother.

• Longitudinal Lie

• Transverse Lie

• Oblique Lie

Occiput (O).

Vertex Presentation Landmark

Mentum (M) or chin.

Face Presentation Landmark

Sacrum (S).

Breech Presentation Landmark

Acromion Process (A).

Shoulder Presentation Landmark

Fetal Position

Described using the side of the maternal pelvis the fetal landmark and whether it is anterior posterior or transverse.

Anterior (A)

The fetal landmark is directed toward the front of the maternal pelvis.

Posterior (P)

The fetal landmark is directed toward the back of the maternal pelvis.

Transverse (T)

The fetal landmark is directed toward the side of the maternal pelvis.

Psychosocial Influences

The fifth P of labor involving emotional psychological cultural and social factors affecting labor.

Catecholamines

Chemicals that affect the nervous and cardiovascular systems metabolism temperature and smooth muscle.

Signs and Symptoms of Impending Labor

Physical and physiological changes indicating labor is approaching.

Lightening

Downward movement of the presenting part into the pelvic cavity.

Timing of Lightening

Usually occurs around 38 weeks in a primigravid pregnancy.

Dropped Baby

Common expression used when the fetus settles into the pelvis.

Symptoms of Lightening

• Leg cramps

• increased pelvic pressure

• increased urinary frequency

• increased venous stasis (lower extremity edema)

• increased vaginal secretions.

Braxton-Hicks Contractions (false labor)

Irregular contractions that prepare the uterus for labor but do not cause cervical change.

• May occur every 10 to 20 minutes near term.

Irregular usually felt in the abdomen or groin and do not cause cervical dilation or effacement.

Characteristics of Braxton-Hicks Contractions

Cervical Ripening

Softening stretching and thinning of the cervix before labor.

Cervical Effacement

The thinning and shortening of the cervix.

Bloody Show

Expulsion of the blood-tinged mucus plug.

• Usually indicates labor may begin within 24 to 48 hours.

Weight Loss Before Labor

Loss of up to 3 pounds due to fluid shifts from hormonal changes.

• Electrolyte shifts and decreased fluid retention caused by changes in estrogen and progesterone.

Gastrointestinal Disturbances

Diarrhea nausea vomiting or indigestion that may occur before labor.

Energy Spurt

Sudden increase in energy near the end of pregnancy.

Nesting

The urge to prepare the home for the baby's arrival.

Premature Rupture of Membranes (PROM)

Spontaneous rupture of the amniotic sac before labor begins.

• Occurs in about 12% of pregnancies.

Amniotomy

Artificial rupture of the amniotic membranes performed by the healthcare provider.

Nitrazine Test

A pH test used to determine whether fluid is amniotic fluid. (ph indicator)
purpose: Detect rupture of membranes by measuring vaginal pH.

Positive Nitrazine Test

Vaginal pH increases due to the presence of amniotic fluid.

Normal Vaginal pH

Between 4.5 and 5.5.

Fern Test

Microscopic examination of vaginal fluid for a ferning pattern.

purpose: Confirm rupture of membranes by identifying ferning.

Positive Fern Test

Presence of crystallization caused by proteins and electrolytes in amniotic fluid.

True Labor

Produces regular contractions with progressive cervical dilation and effacement.

False Labor

Irregular contractions without cervical dilation or effacement.