 [ Symptoms ] what are examples of commonly used medications that are dangerous in pregnancy [ Disease ] many women do not know that over the counter medications can be dangerous in fact many prescription and over the counter medications harm the fetus very early in pregnancy at a time that the mother does not even know she is pregnant even aspirin use by the mother can cause defects in the fetus for this reason as soon as pregnancy is being contemplated women should avoid all over the counter and prescription medications until they are reviewed with the doctor acne medications such as isotretinoin accutane can cause birth defects and should be discontinued before conception since many medications and substances can affect fetal growth and development pregnancy planning is important so that potentially harmful substances can be stopped before conceiving unplanned pregnancy during oral contraceptive use is not felt to pose a significant danger to the fetus although deliberate use of oral contraceptives during pregnancy is not advisable women who become pregnant during oral contraceptive use have the same risk of birth defects in their newborns as the general population of women in the range of 2 3