Antihypertensive utilization patterns among pregnant persons with pre-existing hypertension in the US: A population-based study

by Yanning Wang, Nicole E. Smolinski, Celeste Ewig, Thuy Nhu Thai, Tony S. Wen, Almut G. Winterstein

Hypertension among persons with childbearing potential is on the rise. Maintaining proper blood pressure during pregnancy is vital to prevent maternal and neonatal complications. Yet, limited evidence on the risk-benefit of various antihypertensives presents challenges for informed decision-making during this critical period. This study aimed to examine the utilization patterns of different classes of antihypertensives among persons with pre-existing hypertension before, during, and after pregnancy.

We used MarketScan® Commercial Database 2011−2020 to analyze antihypertensive utilization among pregnant persons aged 12 to 55 identified via a validated algorithm. Pre-existing hypertension was defined as ≥1 inpatient or ≥2 outpatient encounters for hypertension within the 180 days preceding the LMP. Antihypertensive utilization was described during target periods: 0–3 months (0-3M) before pregnancy, 1st/2nd/3rd trimester (T1/2/3), 0-3M, and 4-6M after pregnancy.

We identified 1,950,292 pregnancies, of which 20,576 (12,978 live and 7,598 non-live) had pre-existing hypertension. Both groups had similar antihypertensive use (80.1% and 81.0%, respectively) during the 6 months before pregnancy (baseline). For live-birth pregnancies, 13.9% of baseline users discontinued treatment during pregnancy, while 28.9% of non-users initiated antihypertensives during pregnancy, and 17.2% started postpartum. Before pregnancy, the predominant antihypertensives included thiazide diuretics (21.9%), combined α- and β-blockers (18.4%), and dihydropyridines (16.2%). During pregnancy, thiazide diuretics, cardioselective β-blockers, and ACE inhibitors declined (T3: 3.0%, 4.2%, and 0.8%). Dihydropyridine use was steady during pregnancy, but preference shifted from amlodipine to nifedipine in T3 (2.2.% vs.10.8%). Central α2‐agonists increased during pregnancy (up to 15.2% in T3) compared to both pre- (9.8%) and post-pregnancy (5.7%). ARBs mirrored ACE inhibitors, with less than 1% utilization in later trimesters. Combination agents dropped from 10.8% pre-pregnancy to 0.8% in T3, then rebounded to 7.3% post-pregnancy.

Research is warranted to evaluate the choice of antihypertensives and optimal timing to switch to safer alternatives, considering maternal and fetal outcomes.