Periods of vulnerability Preembryonic period Pregerm(0-2 Wks) Usually Death Embryonic period Organogenesis (3-8 Wks) Abnormalities of form (malformations Fetal period Growth/Maturation( 9 wks birth) Growth retardation Mental dysfunction Fetus vulnerable Rapid cell proliferation o Cell migration o Cell differentiationPeriods of Vulnerability ▪ Preembryonic period Pregerm (0-2 wks) ➢ Usually Death ▪ Embryonic period Organogenesis (3-8 wks) ➢ Abnormalities of Form (malformations) ▪ Fetal period Growth/Maturation (9 wks – birth) ➢ Growth Retardation ➢ Mental dysfunction Fetus vulnerable ⚫Rapid cell proliferation ⚫Cell migration ⚫Cell differentiation