1. Psychology 235 Child Psychology Dr. Blakemore
Prenatal Development
Psychology 235
Child Psychology
Dr. Blakemore

2. Periods of Prenatal Development
Period of the Ovum or Zygote, or Germinal Period - first two weeks
Period of the embryo - 2 to 8 weeks
Period of the fetus - 2 to 9 months

3. Germinal Period- 0 to 2 weeks
Begins with fertilization at about day 14 of a woman’s menstrual cycle
Fertilization takes place in the fallopian tube - producing a zygote
The first cell division takes place within 24 hours
The cell continues to divide. When it reaches the uterus it contains several cells

4. Implantation
Once in the uterus, the fertilized egg is several cells in size -- called a blastocyst
The blastocyst has an inner clump of cells (will become embryo) and an outer layer of cells (will become placenta, membranes, etc.)
The fertilized egg implants in the uterine wall at about days

5. Germinal Period
From Berk, 3rd. Ed. P. 90

6. Period of the embryo 2 to 8 weeks
Begins as a clump of cells about the size of the head of a pin
Ends 6 weeks later fully formed about one inch long
Most important process is differentiation
Very vulnerable time for damage

7. Seven - week embryo
From Berk, 3rd. Edtion, p. 94

8. Period of the Fetus - 2 to 9 months
Growth - increase in size
Beginning of function of organ systems
28 weeks - viability - if born > 50% survive
At birth, 20 inches long, 7 pounds

9. Overview of Prenatal Development
From Berk, 3rd ed., p. 98

10. Prenatal Environment
The baby develops in an environment, which impacts development

11. Prenatal Environment Maternal Age 20 - 35 is ideal Parity
Higher parity, more degradation of prenatal environment, but also impacted by spacing

12. Prenatal Environment Maternal diet
an important consideration is protein
folic acid is also important

13. Prenatal Environment Drugs Can cross placental barrier
most critical during embryonic period
can be teratogens
examples: thalidomide, DES, nicotine, cocaine
Alcohol leads to fetal alcohol syndrome, or fetal alcohol spectrum disorder

14. Prenatal Environment Maternal disease Rubella HIV/AIDS Syphilis
Blindness
Deafness
Mental Retardation

15. Prenatal Environment Zika In first, perhaps also second, trimester
Associated with fetal microcephaly

16. Prenatal Environment
Other influences
radiation, emotional stress