Beta-blockers appear safe during the first trimester of pregnancy, study finds
The drugs were not associated with a significant risk for birth defects in a cohort study of Nordic and American populations.
Beta-blockers used in the first trimester of pregnancy do not appear to be associated with a large increase in the risk for cardiac or other general birth defects, a study found.
Researchers from Brigham and Women's Hospital and Harvard Medical School studied health records for 3.6 million pregnancies, drawn from the registries of the five Nordic countries and a Medicaid data set in the United States, to estimate the risk for major congenital malformations associated with first-trimester exposure to beta-blockers. Results were published Oct. 16 by Annals of Internal Medicine.
Of 3,577 women with hypertensive pregnancies in the Nordic cohort and 14,900 in the U.S. cohort, 682 (19.1%) and 1668 (11.2%), respectively, used beta-blockers in the first trimester. The pooled adjusted relative risk (RR) and risk difference per 1,000 persons exposed associated with beta-blockers were 1.07 (95% CI, 0.89 to 1.30) and 3.0 (95% CI, −6.6 to 12.6), respectively, for any major malformation; 1.12 (95% CI, 0.83 to 1.51) and 2.1 (95% CI, −4.3 to 8.4) for any cardiac malformation; and 1.97 (95% CI, 0.74 to 5.25) and 1.0 (95% CI, −0.9 to 3.0) for cleft lip or palate. For central nervous system malformations, the adjusted RR was 1.37 (95% CI, 0.58 to 3.25) and the risk difference per 1,000 persons was 1.0 (95% CI, −2.0 to 4.0, based on U.S. cohort data only).
“Our analysis was able to exclude a large increase in the relative and absolute risks for overall major malformations and for the most common class of birth defects, cardiac malformations,” the authors wrote. “The potential risks to the fetus must be balanced against the risks to the mother associated with untreated hypertension.”
An accompanying editorial encouraged clinicians to focus on the health of the pregnant woman.
“Whatever might confound the relation between the use of a specific medication in pregnancy and an adverse perinatal outcome, maternal health remains the priority of any clinician or parent,” the editorial stated. “Moreover, fetal well-being depends on maternal well-being, and untreated maternal disease both jeopardizes the health of a fetus and may shorten a pregnancy.”