Alcohol can cause mental retardation, problems with growth, and abnormal facial features. Prescription medicines can also cause problems. Some prescription acne medicines can cause birth defects. So can some medicines used to treat seizures. The antibiotic tetracycline, can cause changes in the baby's teeth and bones if taken late in pregnancy.
Tranquilizers can be addictive to the baby and the mother.
If you take any prescription drugs, talk with your healthcare provider about the effect they may have on your baby. Avoid taking aspirin late in pregnancy. Use of aspirin near the end of pregnancy has caused longer labors, more bleeding during delivery, and an increased chance of stillbirth. Illegal drugs, like cocaine, amphetamines, and marijuana, cause severe problems when used in pregnancy. Babies exposed to cocaine before they are born can have physical and learning disorders.