How do Teratogenic Drugs cause Birth Defects?Teratogenic drugs cause birth defects by damaging the fetus or placenta or umbilical cord; or by causing uterine contractions. Teratogenic drugs can cause birth defects by-Damaging the fetus directlyDamaging the placenta or umbilical cord, thus increasing the risk of birth defectsCausing uterine contractions that can injure the fetus or cause premature deliveryThe kind, nature and frequency of birth defects caused by a teratogen depends on- The property of the drugRate and amount of drug reaching the fetusDuration of exposureStage of the fetal development at the time of exposureEffect of other drugs used in combination Published on Sep 23, 2014Last Updated on Apr 22, 2016