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Beta-blockers safe for pregnant women

Beta-blocker exposure in pregnancy does not increase risk for fetal cardiac anomalies after adjusting for maternal comorbidities, according to a research letter published in JAMA Internal Medicine.

“Beta-blockers are the most commonly used class of medication for treating cardiac conditions in pregnant women. Despite the common use of this class of medication, data that support its safety are limited,” Lewei Duan, MS, from the department of research and evaluation at Kaiser Permanente Southern California, and colleagues wrote. “A recent meta-analysis reported an association between beta-blocker exposure and fetal congenital cardiovascular defects, raising a concern regarding potential teratogenic effects of this class of medication.”

To examine the risk for fetal cardiac malformations in association with maternal beta-blocker exposure, researchers performed a retrospective population-based study of births in the Kaiser Permanente Southern California Region between Jan. 1, 2003 and Dec. 31, 2014. Using pharmacy dispensing records and electronic medical records, they identified women exposed to beta-blockers during pregnancy, maternal comorbidities and fetal congenital anomalies. They used factors that have been shown in other studies to affect fetal congenital anomalies to construct multivariable logistic regression models.

Out of 379,238 pregnancies, 4,847 were exposed to beta-blockers and among those, 2,628 were exposed during the first trimester of pregnancy. The results showed that patients exposed to beta-blockers were older, had higher BMIs and were more likely to have hypertension, preeclampsia, eclampsia, hyperlipidemia, diabetes, heart failure and a history of arrhythmia. In the beta-blocker-exposed group, gestational age at delivery was lower compared with the unexposed group (mean 37.4 weeks vs. 38.9 weeks).

The investigators found that maternal beta-blocker exposure was associated with increased odds of fetal congenital cardiac anomalies in unadjusted analyses; however, there was no association after adjusting for maternal age, maternal BMI and maternal comorbidities. This suggests that the associations seen in the unadjusted analysis were caused by confounders, not the effects conferred by beta-blocker exposure itself.

“The previously reported association between beta-blocker use and fetal cardiac anomalies in other studies may be attributed to confounding,” Duan and colleagues wrote. “While these findings do not definitively rule out the possibility of fetal congenital defects in association with beta-blocker use, these results do provide reassurance regarding the use of this class of medication for the treatment of cardiac conditions in pregnant women.” – by Savannah Demko

Disclosure: The researchers report no relevant financial disclosures.