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

PURPOSE: Prescription drug use during pregnancy has increased during the past decades. However, little is known about prescription drug use for high-risk pregnancies. We aimed to estimate the prevalence of redeemed prescriptions in Danish pregnant women with and without previous psychiatric history.METHODS: A Danish population-based descriptive study of 981 392 pregnancies ending in live-born singletons by 586 988 women aged 15 to 55 years between 1997 and 2012, of which 113 449 (11.6%) pregnancies were by women with a psychiatric history prior to the index pregnancy. All prescription drugs redeemed during pregnancy were identified, and dispensing patterns among the women were reported by therapeutic classes of drugs, calendar year of childbirth, and trimester.RESULTS: Overall, women with psychiatric history prior to pregnancy were more likely to fill a prescription (75.8%; 95% confidence interval [CI], 75.5-76.0%), compared with women with no psychiatric history (64.5%; 95% CI, 64.4-64.6%). The difference was observed even when psychotropic drug use was excluded and in all therapeutic classes except for antineoplastic and immunomodulating drugs. The most commonly prescribed drugs were anti-infectives. Approximately 44.7% (95% CI, 44.5-45.0%) of women with psychiatric history and 31.3% (95% CI, 31.2-31.4%) of women with no psychiatric history redeemed more than one therapeutic class of drugs.CONCLUSIONS: 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.