α/β- and β-Blocker Exposure in Pregnancy and the Risk of Neonatal Hypoglycemia and Small for Gestational Age.

Background: α/β- and β-blockers are essential in pregnant women's perinatal congenital heart disease management. Nevertheless, data on the effects of α/β- and β-blockers on pregnant women and fetuses are limited. We examined the risks of neonatal hypoglycemia and small for gestational age (SGA) associated with maternal exposure to α/β- and β-blockers.

Methods and results: All consecutive pregnant women with heart disease admitted to our hospital between January 2014 and October 2020 were included. Of 306 pregnancies (267 women), 32 were in the α/β-blocker group, 11 were in the β-blocker group, and 263 were in the control group. All 32 pregnancies in the α/β-blocker group were treated with carvedilol. In the β-blocker group, 4 women were treated with bisoprolol, 3 were treated with propranolol, 2 were treated with atenolol, 1 was treated with metoprolol, and 1 was treated nadolol. The incidence of neonatal hypoglycemia was higher in pregnant women taking carvedilol than in the control group (P=0.025). SGA was observed significantly more frequently in pregnant women taking β-blockers than in the carvedilol and control groups (P<0.001).

Conclusions: Carvedilol administration during pregnancy was associated with neonatal hypoglycemia; however, it did not occur in a time- or dose-dependent manner. Routine monitoring of blood glucose levels in newborns exposed to α/β- and β-blockers is essential.