| A | B |
|---|
| period of the embryo | the prenatal period when all major body structures begin to form |
| period of the fetus | the age when viability is attained |
| placenta | the life-giving organ that nourishes the embryo and fetus |
| preterm | a baby born 3 or more weeks early |
| teratology | the scientific study of birth defects |
| reubella | also called German measles |
| HIV | a virus that gradually overwhelms the body's immune responses |
| critical period | term for the period during which a developing baby's body parts are most susceptible to damage |
| neural tube | the precursor of the central nervous system |
| fetal alcohol syndrome | characterized by abnormal facial characteristics slowed growth, behavior problems, and mental retardation |
| germinal period | when implantation occurs |
