Contemporary maternal and fetal outcomes in the treatment of LQTS during pregnancy: Is nadolol bad for the fetus?

BACKGROUND beta-Blocker therapy, specifically nadolol, is the recommended treatment for long QT syndrome (LQTS). Previous studies assessing maternal and fetal outcomes were published before the nadolol era. OBJECTIVE The purpose of this study was to examine contemporary maternal and fetal outcomes in the treatment of LQTS during pregnancy. METHODS We queried the Inherited Arrhythmia Database at Cleveland Clinic and identified all pregnant patients with LQTS from January 2001 through January 2020. Collected data included use and timing of beta-blockers, maternal arrhythmic events, fetal growth restriction, neonatal hypoglycemia, and bradycardia. RESULTS Among 68 live-birth pregnancies in 31 women with LQTS (mean age 29 +/- 5.9 years; mean corrected QT interval 468 +/- 39 ms), there were 5 arrhythmic events in 4 mothers. All arrhythmic events occurred in the postpartum period, and there were no arrhythmic events in patients taking beta-blockers. In patients diagnosed with LQTS and treated with beta-blockers (n=27 [41%]), nadolol was the most commonly prescribed agent throughout pregnancy and the postpartum period (n = 16 [60%]). The rate of intrauterine growth restriction was not significantly different in fetuses exposed to beta-blockers vs unexposed (P = .08). In the postnatal period, hypoglycemia was not seen and 1 patient in the exposure group had bradycardia. CONCLUSION Arrhythmic events were only seen in the postpartum period in those not treated with beta-blockers. Events occurred as late as 9 months postpartum. beta-Blocker therapy, specifically nadolol, was not associated with a higher incidence of intrauterine growth restriction. Moreover, neonatal bradycardia was rare and hypoglycemia was not observed.