Use of prescription and non-prescription drugs in pregnancy. The Baltimore-Washington Infant Study Group.

We analyzed use of therapeutic drugs during pregnancy by 2752 mothers of infants without major congenital malformations. During pregnancy, 68% of the women used at least one prescription or non-prescription drug. Drug use in pregnancy was significantly more common for women who were white, older, married, better educated, of higher income and occupational status, receiving private prenatal care and not living in urban areas. Number of maternal illnesses, higher socioeconomic status, white race, multiparity and use of recreational drugs explained 26% of reported drug use. The mean number of drugs reported (1.2) underestimates total drug exposure due to exclusion of some drug categories including multivitamins and illicit drugs. Since the majority of women giving birth to normal infants report use of at least one pharmacologic agent during pregnancy, attribution of adverse outcome to drug use in an individual case is rarely justified.