Perinatal and Fetal Development - Vocabulary Flashcards

Vocabulary flashcards covering key perinatal and fetal development concepts, structures, processes, and assessments from the notes.

Fertilization

Union of a mature egg cell and a sperm cell at the ampulla, forming a zygote with a complete genetic set.

Zygote

The fertilized egg cell that begins embryonic development.

Morula

A solid ball of 16 cells that forms after several rounds of cell division before the blastocyst.

Blastula

Early embryonic stage with a hollow cavity (blastocoel) and differentiated outer/inner cells.

Blastocyst

Stage with an outer trophoblast and an inner cell mass that implants into the uterus.

Trophoblast

Outer cell layer of the blastocyst that later contributes to the placenta and implantation.

Inner cell mass

Cluster of cells inside the blastocyst that develops into the embryo proper.

Decidua

The endometrium during pregnancy, containing layer changes to support implantation.

Implantation (nidation)

Process by which the blastocyst attaches to and embeds in the endometrium (about 8–10 days after fertilization).

Placenta

Organs connecting mother and fetus; transports nutrients, removes wastes, provides gas exchange, and secretes hormones.

Decidua basalis

Part of the decidua under the site of implantation that contributes to placental formation.

Chorionic villi

Hairlike structures that form the placenta and enable exchange with maternal blood.

Placental barrier

Protective barrier between maternal and fetal blood, allowing some substances to cross.

HCG (human chorionic gonadotropin)

Hormone secreted early in pregnancy; supports corpus luteum and pregnancy; detected by pregnancy tests.

Progesterone

Hormone that maintains pregnancy and prevents uterine contractions.

Estrogen

Hormone involved in mammary development and uterine preparation during pregnancy.

Human placental lactogen (HCS/HPL)

Diabetogenic hormone that modulates maternal metabolism and supports fetal growth; prepares breast for lactation.

Amniotic fluid

Clear to straw-colored fluid surrounding the fetus; 800–1200 mL typically; protects and nourishes the fetus.

Oligohydramnios

Low amniotic fluid volume (<500 mL).

Polyhydramnios

Excessive amniotic fluid (>2000 mL).

Meconium

Fetal stool; green amniotic fluid indicates meconium passage before birth.

Golden amniotic fluid

Yellowish amniotic fluid indicating possible fetal hemolytic disease.

Umbilical cord

Cord connecting fetus to placenta; contains two arteries and one vein, surrounded by Wharton’s jelly.

Wharton’s jelly

Gelatinous substance that cushions the umbilical vessels to prevent cord compression.

AVA (artery, vein, artery)

Three-vessel cord arrangement: two arteries and one vein.

Foramen ovale

Fetal heart shunt from right atrium to left atrium, bypassing the lungs.

Ductus arteriosus

Fetal shunt from pulmonary artery to aorta, bypassing the lungs.

Ductus venosus

Shunt that bypasses the liver by routing oxygenated blood from the umbilical vein to the inferior vena cava.

Fetal circulation

Circulation scheme in the fetus that bypasses non-functioning lungs and liver via shunts (foramen ovale, ductus arteriosus, ductus venosus).

Age of viability

Approximately 20–24 weeks; fetus with potential to survive outside the uterus with support (>500 g).

Pre-embryonic stage

First 1–2 weeks post-fertilization; early development and differentiation may be damaged by teratogens.

Embryonic stage

3–8 weeks; organogenesis; most sensitive period to teratogens.

Fetal stage

8 weeks to birth; post-differentiation; most congenital malformations unlikely but growth issues possible.

Germ layers

Ectoderm (nervous system, skin), Mesoderm (musculoskeletal, circulatory), Endoderm (GI tract lining, respiratory tract).

Ectoderm

Germ layer forming the nervous system, skin, and related structures.

Mesoderm

Germ layer forming muscles, skeleton, circulatory, and urogenital systems.

Endoderm

Germ layer forming the lining of the GI and respiratory tracts and associated organs.

Fetal breathing movements

Fetal respiratory activity detectable by ultrasound; relates to lung development and surfactant production.

Surfactant

Phospholipid that reduces alveolar surface tension; essential for postnatal breathing.

Lecithin/Sphingomyelin ratio (L/S)

Ratio used to assess fetal lung maturity; ratio of 2:1 suggests viability of lungs.

Betamethasone

Corticosteroid given to promote fetal lung maturity by stimulating surfactant production.

Lanugo

Fine downy hair covering the fetus; appears around 16 weeks, regresses before birth.

Vernix caseosa

Creamy protective coating on the fetus’s skin; formed by 20 weeks; sheds before birth.

IgG

Maternal antibodies that cross the placenta, providing temporary passive immunity to the fetus.

IgA/IgM

Antibodies produced by the fetus after infection; do not cross the placenta in significant amounts.

Amniocentesis

Ultrasound-guided sampling of amniotic fluid (18–30 weeks) for diagnostic tests; risks include miscarriage and infection.

Cordocentesis (PUBS)

Percutaneous umbilical blood sampling to test fetal blood in the 2nd–3rd trimester.

Fetoscopy

Visualization of the fetus using a fetoscope, typically around 16–17 weeks.

Biophysical Profile (BPP)

Prenatal test combining fetal ultrasound and heart rate monitoring to assess fetal well-being (breathing, movement, tone, amniotic fluid, NST).

MBPP (Modified Biophysical Profile)

A simplified BPP with emphasis on amniotic fluid index and NST.

Naegele’s rule

Estimated due date: LMP minus 3 months plus 7 days (adjust year as needed).

McDonald’s rule

Fundal height in cm roughly equals weeks of gestation (mid-pregnancy).

Johnson’s rule

Estimates fetal weight using fundal height (n x 155) with n depending on fetal engagement.

Sadovsky method

Monitoring fetal movements after a meal to assess well-being; target ~10 movements per hour.

Cardiff Count to Ten

Home method counting time to 10 fetal movements, similar to Sadovsky but using a chart.

Nonstress testing (NST)

FHR reactivity test; reactive if two accelerations of 15 bpm for 15 seconds within 20 minutes.

Contraction Stress Test (CST)

Tests fetal response to contractions (often via oxytocin or nipple stimulation); negative if no decelerations with 3 contractions.

Vibroacoustic stimulation

Audible stimulation to awaken the fetus during testing to elicit movement.

Ultrasound

Imaging tool to confirm pregnancy, fetal size, location, anatomy, and sex; uses gel and may include Doppler for blood flow.

Placental grading

Ultrasound-based staging (0–3) of placental maturity across gestation.

Teratogens

Substances or factors that can cause fetal malformations or growth defects.

FDA pregnancy categories

A–X categories assessing risk of medications during pregnancy; A is safest, X is contraindicated.

Nurse’s fetal assessment history tools

History taking, fundal height, and fetal well-being monitoring are part of prenatal assessment.