Background: Antidepressants are among the most common prescriptions in women of childbearing age with increasing prescribing in recent decades. There is some evidence to suggest that many women stop antidepressants abruptly on becoming pregnant. It is important to understand contemporary patterns of antidepressant prescribing during pregnancy.
Objectives: To perform a population-based drug utilization study using the UK Clinical Practice Research Datalink (CPRD) to characterize prescriptions of antidepressants before, during, and after pregnancy, including discontinuation and initiation during pregnancy.
Methods: Having defined a cohort of eligible pregnancies in the CPRD Pregnancy Register, we identified women prescribed antidepressants in the 12 months before, during, and the 12 months after pregnancy using primary care prescription data. Of those prescribed antidepressants during pregnancy, we categorized them as either prevalent or incident users. Prevalent users were defined as those who had at least one prescription of antidepressants in the 3 months prior to pregnancy and incident users were those who did not have any antidepressant prescriptions in the 3 months prior to pregnancy. Among these two groups, we investigated patterns of prescribing within pregnancy: discontinuation, dose changes, medication switching, and continuation with no changes to their regimen.
Results: Of the 30,804 pregnancies exposed to antidepressants between 1996 and 2018, 24,219 (79%) had been prescribed antidepressants in the 3 months prior to pregnancy (prevalent users). The remaining 21% were incident users during pregnancy (no prescriptions in the 3 months before the start of pregnancy). The majority of women who used antidepressants during pregnancy discontinued (78% and 81% for prevalent and incident users, respectively). Of those who continued antidepressants throughout pregnancy, dose reduction was more common among prevalent users, whereas increasing dose was more common among incident users. However, not changing regimen was the most common pattern in both prevalent and incident users who continued their antidepressants throughout pregnancy (47% and 69%, respectively). When looking in the immediate postpartum period, the majority of those who discontinued during pregnancy resumed antidepressants 12 months after the end of pregnancy (64%).
Conclusions: Most women prescribed antidepressants in pregnancy in the UK are prevalent users who are already prescribed these medications prior to pregnancy. A substantial proportion of these prescriptions are discontinued in early pregnancy but reinitiate after the pregnancy has ended.
