Prenatal development and birth

Question 1

Prenatal development

Answer 1

-Periods between conception and birth (38 weeks): 1 cell zygote, embryo and 200-billion cell fetus

Question 2

Period of Zygote

Answer 2

• Lasts 2 weeks from contraception
• First cell division takes 30 hours
• After 4 days blastocyst forms (60-80 cells), after 10-14 days it implants onto uterine wall
• Only 1/4 zygotes survive this stage

Question 3

Period of embryo

Answer 3

• Inner layer of blastocyst becomes embryo and outer layer forms protective tissue. Embryo becomes 10,000 times bigger than zygote 1 month after conception.
• Virtually all structures have finished or started forming

Question 4

Period of fetus

Answer 4

• o Last 7 months of pregnancy
• At the end of month 3 organ systems grow, refine and begin integrating
• Second trimester: heartbeat, thumb sucking, kicking felt, can see and hear
• Third trimester: cycles e.g. heartbeat and sleep become more regular
• Miracle babies born at 21 weeks can survive but may have developmental problems

Question 5

Environmental influences on prenatal development

Answer 5

• External agents (teratogens) can harm development, especially during sensitive periods (embryogenesis and fetogenesis) that are critical for organ development
• Exposure to father can cause chromosomal damage and have long-term effects

Question 6

Alcohol effects

Answer 6

• Fetal alcohol syndrome/Fetal Alcohol Spectrum Disorder has serious effects (small head: poor speech and motor function) and problems with underdeveloped hearth, limbs, joints, face
• Fetal alcohol effects (FAE): smaller effects of moderate alcohol use

Question 7

Smoking

Answer 7

-Lower birth weight, depression, miscarriage, death

Question 8

Recreational effects

Answer 8

• Heroin: premature birth, infants born addicted, persistent distress
• Cocaine: early reports exaggerated the effects
• Marihuana: weakest effects, perhaps later attention and memory problems

Question 9

Prescription drugs

Answer 9

• Thalidomide: caused major physical birth defects
• Folic acid: prevents Spina Bifida
• Overdose of vitamin A can be dangerous

Question 10

Parental charagteristics

Answer 10

• Mothers diet should be varied, nutritious or supplemented with vitamin/minerals
• Optimal child-bearing age: 20s and 30s

Question 11

Parental characteristic issue

Answer 11

• Recent trend of having babies late
• Teenage pregnancies
• Overweight and obese mothers

Question 12

Labour

Answer 12

• Three stages, first is longest especially for first time mothers
• Medication can be given but personal choice is important
• Venue depends on choice and availability
• Apgar test checks heart rate, breathing and reflex irritability
• Other standardized tests (e.g., Brazelton’s NBAS) after

Question 13

Birth complications

Answer 13

• Anoxia: Baby suffers oxygen deprivation common in breach babies so caesarian may be needed, serious after 3-4mins
• Low birth weight seen in preterm infants (may show respiratory distress syndrome)
• Babies may be difficult; interventions for parents help
• 95% of babies are born with no defects or major complications