Summary

Background:

The need for postnatal monitoring of infants exposed to intrauterine beta blockers (BBs) has not been clearly defined.

Objectives:

To evaluate infants exposed to intrauterine BBs in order to estimate the need for postnatal monitoring.

Methods:

This retrospective case-control study comprised 153 term infants born to mothers who had been treated with BBs during pregnancy. Treatment indications included hypertension 76 mothers (49.7%), cardiac arrhythmias 48 (31.4%), rheumatic heart disease 14 (9.1%), cardiomyopathy 11 (7.2%) and migraine 4 (2.6%). The controls were infants of mothers with hypertension not exposed to BBs who were born at the same gestational age and born closest (before or after) to the matched infant in the study group.

Results:

Compared to the control group, the infants in the study group had a higher prevalence of early asymptomatic hypoglycemia (study 30.7% vs. control 18.3%, P = 0.016), short symptomatic bradycardia events, other cardiac manifestations (P = 0.016), and longer hospitalization (P < 0.001). No life-threatening medical conditions were documented. The birth weight was significantly lower for the high-dose subgroup compared to the low-dose subgroup (P = 0.03), and the high-dose subgroup had a higher incidence of small-for-gestational-age (P = 0.02).

Conclusions:

No alarming or life-threatening medical conditions were observed among term infants born to BB treated mothers. These infants can be safely observed for 48 hours after birth close to their mothers in the maternity ward. Glucose follow-up is needed, especially in the first hours of life.