Antihypertensive drugs and the risk of congenital anomalies.

STUDY

OBJECTIVE

To estimate the prevalence of congenital anomalies among the offspring of women exposed and unexposed to antihypertensive drugs during early pregnancy.

DESIGN

Matched cohort study.

DATABASE: The United Kingdom's General Practice Research Database.

SUBJECTS: Women exposed to antihypertensive drugs during early pregnancy and a sample of matched unexposed pregnant women.

MEASUREMENTS AND MAIN

RESULTS

The prevalence of any anomaly among unexposed and exposed women was 23.5 (95% confidence interval [CI] 14.4-38.3) and 20.9 (95% CI 10.0-43.8) per 1000 pregnancies, respectively (relative risk [RR] 0.9, 95% CI 0.4-2.2). The relative risk of limb anomalies among women exposed to β-blockers was 6.4 (95% CI 0.6-70.1). Exposure to angiotensin-converting enzyme (ACE) inhibitors, β-blockers, and calcium channel blockers increased the risk of genital anomalies (RR 3.8, 95% CI 0.9-16.0; RR 2.8, 95% CI 0.7-11.9; RR 1.3, 95% CI 0.1-12.4, respectively).

CONCLUSION

ACE inhibitors prescribed in the first trimester of pregnancy appeared to increase the risk of congenital anomalies among the offspring of exposed women (RR 2.5, 95% CI 0.5-13.5). These drugs should be avoided in women planning to become pregnant. A marginally increased risk was also found with exposure to β-blockers (RR 1.4, 95% CI 0.6-3.3). These findings are based on small numbers and are not statistically significant.