Processes of Birth - Key Terms (Vocabulary Flashcards)

A set of vocabulary flashcards covering the major concepts related to the process of birth from the provided notes.

Contractions (labor)

Coordinated, involuntary, intermittent uterine contractions that begin in the fundus and move downward to dilate the cervix and propel the fetus.

Contraction cycle

Cycle of increment (increasing strength), peak (acme), and decrement (relaxation); with interval between contractions, describing frequency, duration, and intensity.

Resting tone

Uterine tone between contractions, described as soft/relaxed or firm.

Effacement

Thinning and shortening of the cervix, expressed as a percentage of the original cervical length (100% = fully effaced).

Dilation

Opening of the cervix measured in centimeters; full dilation is about 10 cm.

Nullipara

A client who has not completed a pregnancy of at least 20 weeks.

Parous

A client who has given birth after a pregnancy of at least 20 weeks.

Cardiovascular changes during labor

Contractions temporarily shunt blood back into circulation (300–500 mL), raising blood volume; vital signs best between contractions; supine position can reduce cardiac output.

Respiratory changes during labor

Increased depth and rate of respirations; risk of hyperventilation and respiratory alkalosis if breathing becomes rapid and shallow.

Gastrointestinal changes during labor

Reduced gastric motility; nausea/vomiting; guidelines often allow clear liquids; solid foods may be avoided in some settings.

Urinary changes during labor

Reduced sensation of a full bladder; full bladder can impede fetal descent and increase infection risk.

Hematopoietic changes during labor

Normal blood loss ~500–1000 mL; blood volume increases 40–45% during pregnancy; leukocytosis may occur; clotting factors rise (fibrinogen) increasing thrombosis risk.

Placental exchange during contractions

Exchange of oxygen/nutrients/waste occurs in intervillous spaces; flow decreases during contractions and resumes between contractions.

Fetal protective mechanisms

Fetal Hgb F, high Hgb/Hct, and high cardiac output aid oxygen delivery and adaptation to extrauterine life.

Fetal heart rate (normal range)

Typically 110–160 bpm; preterm fetuses may have higher rates due to immature parasympathetic control.

Fetal lung fluid clearance

Lung fluid clearance accelerates during labor; ~35% remains at birth; remaining fluid is absorbed or expelled during birth.

Catecholamines in the fetus

Epinephrine and norepinephrine help with heart and lung adaptation, fluid clearance, and temperature regulation during birth.

Four Ps of the birth process

Powers (forces), Passage (birth canal), Passenger (fetus), Psyche (emotional state) — interacting to determine labor course.

Powers

Forces moving the fetus through the birth canal: uterine contractions (primary) and voluntary bearing-down (secondary).

Passage

The birth canal, including the pelvis and soft tissues; true pelvis is most critical; divisions include inlet, midpelvis, outlet.

Passenger

The fetus, membranes, and placenta; fetal head, sutures, and fontanels influence molding and position.

Fetal presentation

The part of the fetus that enters the pelvis first: cephalic, breech, or shoulder (cephalic most common).

Cephalic presentations

Variations of head-first presentation: Vertex, Military, Brow, and Face.

Breech presentations

buttocks or feet presenting first; variations include Frank, Complete, and Footling.

Shoulder presentation

Shoulder presenting in a transverse lie; very rare and often requires cesarean delivery if viable.

Fetal position abbreviations

Descriptors like LOA (left occiput anterior) show the fetus’s landmark relative to the maternal pelvis using letters R/L, O/M/S, and A/P/T.

Biparietal diameter

Major transverse diameter of the fetal head, averaging about 9.5 cm at term.

Suboccipitobregmatic diameter

Smallest presenting AP head diameter when the head is fully flexed, also around 9.5 cm.

Fetal lie

Orientation of the fetus’s long axis to the mother's; most are longitudinal; rare transverse or oblique.

Fetal attitude

Relation of fetal body parts; normal attitude is flexed (head toward chest); extension is abnormal (face presentation).

Latent phase (first stage)

Early labor with gradual cervical effacement/dilation; now viewed as 0–5/6 cm in many cases.

Active phase (first stage)

Faster cervical dilation (often 5–6 cm to 10 cm); contractions become more frequent and intense.

Friedman curve

Historical model placing active labor around 4 cm; modern data show slower progress and active labor often begins around 5–6 cm.

Second stage

From full dilation to birth; pushing with contractions; “laboring down” may occur; duration varies by parity and analgesia.

Third stage

Placental stage; from birth of the baby to expulsion of the placenta; typically about 6 minutes.

Fourth stage

First few hours after birth; physical recovery; uterus size/firmness; lochia; bonding and breastfeeding initiation.

Lochia

Postpartum vaginal discharge: rubra (red), serosa (pink/brown), alba (white/yellow) in successive stages.

Premature rupture of membranes (PROM)

Membrane rupture before onset of labor; risks include infection and cord compression; requires evaluation.

Braxton Hicks contractions

Irregular, mild contractions near term that may become more noticeable and sometimes painful.

Lightening

Descent of the fetal presenting part toward the pelvic inlet before labor; relieves diaphragmatic pressure but increases urinary frequency.

Bloody show

Mucus plus pink/brown blood from ruptured cervical capillaries; may precede labor by days/weeks, especially in first pregnancies.

Nesting energy

Sudden surge of energy before labor; guidance to conserve energy and avoid exhaustion.

Weight loss before labor

Small weight loss (approximately 1–3 lb or 0.9–1.4 kg) due to fluid shifts and hormonal changes.

True labor

Contractions become regular, increase in intensity and frequency, and cause progressive cervical change (effacement and dilation).

False labor

Irregular contractions without progressive cervical change; may lessen with activity and do not produce sustained cervical dilation.

Impact of technology in birth

Technology aids monitoring but can feel impersonal; nurses should balance data with focus on the client, fetus, and family.