Beta-blockers in pregnancy – how safe are they?

This study investigated the risk associated with beta-blocker use in pregnant women with hypertension.

They found that beta-blocker use in the first trimester was not associated with an increase in birth defects.

Hypertension (high blood pressure) is common in pregnancy. Some women may have a history of hypertension, others may develop it during the pregnancy. Managing blood pressure (BP) in pregnancy is very important. Hypertension can be dangerous for both the mother and fetus.

One type of medication to treat hypertension are beta-blockers. These drugs block beta-adrenergic receptors. A hormone called epinephrine (EP) usually binds to these receptors. Beta-blockers prevent EP from working and the heart relaxes. Slowing the heart rate reduces the amount of blood being pumped and therefore lowers BP. The safety of using beta-blockers during pregnancy is not clear. These drugs can cross the placenta. There is some concern that beta-blockers may have a negative effect on fetal (baby) development.

This study included a total of 18,477 pregnant women with hypertension. The authors compared women that had taken beta-blockers as anti-hypertensive medication (12.7%) during the first trimester of the pregnancy to those that had not. They looked at the rate and type of malformations (defects) in babies born to these women.  

The rate of defects was similar in women that took anti-hypertensives in the first trimester. The rate of heart defects was also similar in both groups. There was no difference in the risk of cleft lip or brain defects.

The authors concluded that beta-blocker use in the first trimester was not associated with an increase in the risk of birth defects.

This study only included live births in the assessment. We do not know if anti-hypertensive medication cause defects in lost pregnancies. This subject needs further investigation. Managing BP during pregnancy is vital to ensure the health of the mother and child.

If you have concerns regarding hypertension and pregnancy, please discuss this with your physician.