Prescription drug use in pregnancy and variations according to prior psychiatric history.

Women with a psychiatric history were more likely to redeem prescriptions during pregnancy across almost all drug classes, especially anti-infectives. Two thirds of all women redeemed at least one prescription drug during pregnancy and one third more than one drug class. KEY POINTS We mapped prescription drug use of almost 600 000 women during almost one million pregnancies with focus on women with a history of psychiatric disorder before conception compared with women with no such history. Pregnant women with a previous psychiatric disorder were more likely to redeem prescription drugs compared with pregnant women without a previous psychiatric disorder. The observed overall difference was not due to obvious differences in psychotropic drug use. The difference was evident across calendar years, all trimesters, and almost all drug classes, but to a large extent in anti-infectives, among those mainly antibiotics. Two thirds of pregnant women redeemed prescription drugs during pregnancy, and one third redeemed more than one drug class. Health professionals should be aware of comorbid conditions requiring multiple drug use during pregnancy with the risk of unknown fetal effects.