Chapter 10: Human Development Across the Life Span Progress Before Birth: Prenatal Development 3 phases germinal stage = first 2 weeks conception, implantation, formation of placenta embryonic stage = 2 weeks ? 2 months formation of vital organs and systems fetal stage = 2 months ? birth bodily growth continues, movement capability begins, brain cells multiply age of viability Figure 10.1 Overview of fetal development Environmental Factors and Prenatal Development Maternal nutrition Malnutrition linked to increased risk of birth complications, neurological problems, and psychopathology Maternal drug use Tobacco, alcohol, prescription, and recreational drugs Fetal alcohol syndrome Environmental Factors and Prenatal Development Maternal illness