A cohort study of antihypertensive use during pregnancy in South Korea, 2013-2017.

Abstract

Hypertensive disorder is a common medical condition in pregnancy. However, the recommendations for antihypertensive use during pregnancy are based on limited evidence and various factors affect their selection in clinical practice. We aim to assess the prevalence of antihypertensive use and describe which medications are being used in pregnancy. We conducted a cohort study of all pregnancies resulted in a live birth between 2013 and 2017, by using the Health Insurance Review and Assessment (HIRA) database of South Korea. Based on duration of drug supplied, we examined antihypertensive use during the pre-pregnancy, pregnancy, and postpartum periods. We described the patterns of discontinuing, continuing, switching, and initiating antihypertensive medications during pregnancy. We included 2,030,821 pregnancies, of whom 0.9%, 3.1%, and 1.8% were dispensed antihypertensives in the pre-pregnancy, pregnancy, and postpartum periods, respectively. The most frequent medications used were dihydropyridines (40.7%), beta-blockers (38.4%) and Angiotensin II Receptor Blockers (16.8%) in the first trimester, and dihydropyridines (89.7%) and vasodilators (11.5%) in the third trimester. Among women exposed to antihypertensives during pregnancy, this was the first use in 86.3% of women. Among women receiving antihypertensives before pregnancy, 77.9% discontinued treatment during pregnancy, whereas 13.2% continued to take their pre-pregnancy medications. The prevalence of antihypertensive use during pregnancy was 3.1% in South Korea. Overall, while dihydropyridines were predominant, other types of antihypertensives were also commonly dispensed during pregnancy. It suggests a need to investigate the effect of exposure to various types of antihypertensives of which safety remains unclear during pregnancy.