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Beta-blockers safe in early pregnancy

Use of beta-blockers in the first trimester of pregnancy was not associated with a significant risk for major congenital malformations, according to research published in Annals of Internal Medicine.

“Chronic hypertension is increasingly prevalent in pregnancy, likely because of the higher prevalence of obesity in women of reproductive age and increasing maternal age at the time of pregnancy,” Brian T. Bateman, MD, MSc, from Brigham and Women’s Hospital and Harvard Medical School, and colleagues wrote.

“Because antihypertensive medications are used frequently in early pregnancy, understanding whether beta-blockers increase the risk for congenital malformations is a research priority,” they added.

Bateman and colleagues conducted a cohort study to determine the association between first-trimester exposure to beta-blockers and the risk for major congenital malformations, including cardiac malformations, cleft lip or palate, and central nervous system malformations.

The researchers examined the health records for 3.6 million pregnancies from the U.S. Medicaid database (U.S. cohort) and the health registries of Denmark, Finland, Iceland, Norway and Sweden (Nordic cohort) for first-trimester exposure to beta-blockers and major congenital malformation outcomes.

They identified 14,900 women with hypertensive pregnancies in the U.S. cohort and 3,577 in the Nordic cohort. In the first trimester, 11.2% of pregnant women with a diagnosis of hypertension from the U.S. cohort were exposed to beta-blockers, as were 19.1% from the Nordic cohort.

Overall, the exposure to beta-blockers in the first trimester was associated with no risk for any major malformation (RR = 1.07; 95% CI, 0.89-1.3; risk difference per 1,000 persons exposed [RD] = 3; 95% CI, 6.6-12.6), but a slightly increased risk for any cardiac malformation (RR = 1.12; 95% CI, 0.83-1.51; RD = 2.1; 95% CI, –4.3-8.4), cleft lip or palate (RR = 1.97; 95% CI, 0.74-5.25; RD = 1; 95% CI, –0.9 to 3) and central nervous system malformations (RR = 1.37; 95% CI, 0.58-3.25; RD = 1; 95% CI, 2-4).

“Our study cannot exclude an increase in the RR for the less common malformation types, cleft lip or palate and central nervous system malformations. However, the point estimates from our analysis suggest a more modest increase in the RR for these malformations than earlier publications have reported. The potential risks to the fetus must be balanced against the risks to the mother associated with untreated hypertension,” Bateman and colleagues concluded.

In an accompanying editorial, Joel G. Ray, MD, MSc, St. Michael’s Hospital, University of Toronto, Canada, wrote that untreated maternal disease may negatively impact the health of a fetus and may shorten the length of a pregnancy.

“Accordingly, beta-blockers should be used in pregnancy when indicated for the treatment of various maternal medical conditions, and labetalol should be a first-line treatment choice for chronic hypertension,” he concluded. – by Alaina Tedesco

Disclosures: Bateman reports receiving grants from Baxalta, GlaxoSmithKline, Lilly, NIH, Pacira and Pfizer outside the submitted work. Please see study for all other authors’ relevant financial disclosures. Ray reports no relevant financial disclosures.