Abstract Body (Do not enter title and authors here):
Background: Due to teratogenic risks of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB), the current guideline recommends prescribing ACEI and ARB for women of childbearing age concurrently with contraceptives to prevent unexpected pregnancy. However, adherence to this guideline in patient care settings is unknown.

Research Hypothesis: This study examines patterns of concomitant contraceptive use with antihypertensive treatment and pregnancy outcomes among women of reproductive ages using Veterans Affairs electronic health records data.

Methods: The study includes 131,598 women veterans and active military service members aged 20-50 on antihypertensive medication who received care from the Veterans Health Care System or the Military Health System between January 1, 2007 to December 31, 2022. Average age of women was 39 years, and majority (45.5%) were Non-Hispanic White (Table 1). Types of contraceptive medication include combined oral contraceptive pills (yaz, ortho tri-cyclen), progestin-only pills (emicronor), vaginal rings (NuvaRing), transdermal patch (Ortho Evra), and injection (Depo-Provera).

Results: The most prescribed antihypertensive medication were beta blockers (43.78%), followed by diuretics (39.91%), alpha blockers (32.80%) and ACEI/ARBs (30.79%, n=40,518). Twelve percent (n=4,862) of those on an ACEI/ARB (n=40,518) were concurrently on contraceptives, while 17% and 19% of those on beta blockers and alpha blockers were concomitantly on contraceptives, respectively. Furthermore, 1.5% (n=588) women on ACEI/ARB, 3.5% on beta blockers, and 3.7% on alpha blockers were pregnant (Figure 1). An increasing number of women were prescribed an ACEI/ARB over 12 years (p=0.0089), but the percent of women concurrently on ACEI/ARBs and contraceptives has significantly decreased (p=0.0022; Figure 2).

Conclusion: Despite the current guideline, very low concomitant use of contraceptives (12%) with ACEI/ARB was observed in the study. While ACEI/ARB is the least prescribed medication to treat hypertension for reproductive age women, its use has been steadily increasing over the past decade, while rates of concurrent contraceptive use has decreased placing women at an increased risk of teratogenic exposure during pregnancy. Future studies are warranted to investigate the cause and barriers of suboptimal concomitant contraceptive utilization with ACEI/ARBs and pregnancy outcomes, including low birth weight and preterm delivery.