Beta Blockers During Pregnancy Not Linked To Risk Of Congenital Malformations: Study

Use of beta blockers during the first trimester of pregnancy does not appear to increase the risk of congenital birth malformations, according to the findings of an international study. 

Researchers followed pregnant women from both the U.S. and five Nordic countries who had hypertension, to determine if taking beta blockers, such as Lopressor or InnoPran XL, affected their children. Beta blockers were not linked to an increased risk for any malformation, according to the findings published late last month in the journal Annals of Internal Medicine.

Researchers from the U.S. and European Union compiled data from heath registries in five nordic countries and data from the U.S. Medicaid database on more than 18,500 pregnant women with a diagnosis of hypertension and data on their babies.

During the first trimester, approximately 19% of women in the Nordic study used beta blockers, while 11% in the U.S. used them. According to the findings, women who used beta blockers during pregnancy did not increase the risk of their child having any major malformation, cardiac malformation, or cleft lip or cleft palate.

Beta blockers included drugs like Lopressor, Toprol-XL, or Zebeta, which are a class of antihypertensive medications used to lower blood pressure. The drugs work to block the effects of epinephrine. They are the most commonly used class of medication to treat cardiac conditions during pregnancy and are often prescribed to manage arrhythmias or prevent subsequent heart attacks.

Many doctors are wary of the effect beta blockers may have during pregnancy because of the drug’s ability to cross the placenta and potentially cause changes to the fetus.

Other studies have shown a link between beta blockers and bradycardia and hypoglycemia in infants.

However, a study published in 2017 also indicated beta blockers seem to pose no risk to the fetus. The study concluded women who take the drug during pregnancy do not increase their child’s risk of having heart problems in utero.

The new study, much like the study from 2017,  does not definitely rule out the connection between beta blocker use during pregnancy and increased risks to the infant. However, it does indicate fetal malformations are not a common occurrence among infants born to mothers who use beta blockers like Lopressor or InnoPran XL.