Teratogens: Substances that can cause malformations or defects in embryo or fetus.
 
Substance Observed Effects
Nicotine - one or more packs of cigarettes per day Low birth weight

Hyperactivity
Cocaine Exposure when an embryo may result in mental retardation

Exposure when a fetus may result in hyperactivity, motor problems
Alcohol 1-2 drinks/day:
  • Attention deficit disorder 
  • 5 points lower IQ at age 4
3-5 drinks/day: fetal alcohol syndrome (mental retardation, facial deformities, extra toes and fingers)
Lead in environment Memory problems, low verbal intelligence
Herpes Brain damage, miscarriage (if birth canal is infected)