Chapter 3: prenatal development Flashcards
Prenatal Development
Development of an organism from
conception through birth
Stages of prenatal development
Germinal Stage
Embryonic Stage
Fetal Stage
Germinal stage
Conception to 2 Weeks
Cell differentiation and implantation occur
CRITICAL POINTS:
- Hormonal changes make implantation optimal at 9
days, but less likely AFTER 9 DAYS
- Upon implantation, embryo begins to take nutrients from mother’s blood, and is now vulnerable to TERATOGENS
- Excessive alcohol consumption especially dangerous
- Hormonal changes cause fatigue, nausea, and swollen breasts
Embryonic Stage
Week 3 through 8
Differentiation continues
CRITICAL PERIODS OF DEVELOPMENT:
- Differentiation and growth occur rapidly
- Essential structures form
- Embryo is highly vulnerable to: GENETIC ABNORMALITIES and ENVIRONMENTAL INFLUENCES THAT AFFECT CELL DIVISION AND/OR DAMAGE EMBRYO
– Organogenesis: embryo is now a fetus
Fetal Stage
Week 9 to Birth
Weeks 9-12: sex organs develop
Ultrasound at 14 weeks-20 wks
CRITICAL POINT: Weeks 26 to 28
- Fetus viable if born premature due to mature lungs
- 22-24 weeks potentially viable with assistance
Weeks 28 to 40:
- Rapid weight gain (5 lbs)
- Organ systems fully formed
- Brain develops rapidly
Birth: Average length 19 to 21 in.; weight= 7-7.5 lbs
Threats during gestation:
TERATOGENS
Environmental factors that can cause birth defects
Germinal stage: low risk
Embryonic stage: highest risk
Fetal stage: moderate risk
Most common teratogen: alcohol
Maternal Age
Mothers under 15 and older than 40: higher risk of low birth weight
Young mothers: GxE Interaction
Non-Hispanic black mothers have higher risk of LBW across reproductive lifespan→ GxE Interaction
Psychological Adjustments to
Having a Newborn
Parents must adjust to changes in:
- Relationship: couplehood vs parenthood
- Work / Career
- Finances
- Daily hassles/stress
Physical changes:
- Fatigue, breastfeeding, sleep deprivation
- Child Temperament and individual needs
- Other siblings, older dependent parents
