Prenatal Development and Birth

What is the length of pregnancy from conception?

• 38 weeks

• 266 days

What is the length of pregnancy based on gestational age?

• 40 weeks

• 280 days

What is the timeframe for a full-term pregnancy?

• 39 weeks to 40 weeks 6 days

When does the Germinal Period occur?

• Conception to implantation

• Approximately two weeks

What key cellular processes begin in the Germinal Period?

• Rapid cell division

• Cell differentiation

What percentage of zygotes do not survive the Germinal Period?

• Approximately 50 percent

When does the Embryonic Period occur?

• Third to eighth week after conception

What major developmental milestone occurs during the Embryonic Period?

• Organogenesis

What body structures develop from the ectoderm?

• Hair and skin

• Nervous system

What body structures develop from the mesoderm?

• Muscles and bones

• Circulatory system

What body structures develop from the endoderm?

• Digestive system

• Lungs

When do the beginnings of the brain form?

• 3 to 4 weeks gestation

How does the neural tube form?

• The neural plate folds up

What birth defect is associated with neural tube issues?

• Spina bifida

When does the Fetal Period occur?

• Ninth week after conception until birth

When is the sex organ typically visible via ultrasound?

• At 3 months gestation

When is the fetal heartbeat first detectable via stethoscope?

• At 20 weeks gestation

What is quickening and when does it occur?

• First felt fetal movements

• 18 to 20 weeks

What is the age of viability for a fetus?

• 22 weeks gestation

When does brain cell proliferation occur?

• 10 to 20 weeks gestation

When does brain cell migration occur?

• 12 to 24 weeks gestation

When does synaptogenesis begin in the brain?

• 20 weeks gestation to puberty

When does myelination of the brain occur?

• 24 weeks gestation to 10 years

What are the major physiological changes in the final trimester?

• Extensive cortex folding

• Lung expansion and contraction

What is a teratogen?

• Any environmental agent harming a developing fetus

What are the teratogenic effects of tobacco?

• Low birth weight

• Preterm birth

How is the start of labor triggered?

• Fetal brain signals hormones to contract uterine muscles

What occurs during Stage 1 of labor?

• Uterine contractions begin

• Cervix enlarges to 4 inches

What occurs during Stage 2 of labor?

• Fetus passes through cervix

• Baby is born

What occurs during Stage 3 of labor?

• The placenta is expelled

What is anoxia during birth?

• Oxygen deprivation to the infant

What daily supplement is highly recommended for prospective mothers?

• Multivitamin with folic acid