A management strategy for fetal immune-mediated atrioventricular block.

Introduction: The purpose of this study is to describe an in utero management strategy for fetuses with immune-mediated 2° or 3° atrioventricular (AV) block.

Methods And Results: The management strategy as applied to 29 fetuses consisted of three parts. First, using fetal echocardiography and obstetrical ultrasound, we assessed fetal heart rate (FHR), heart failure, growth and a modified biophysical profile score (BPS) assessing fetal movement, breathing and tone. Second, we treated all fetuses with transplacental dexamethasone, adding terbutaline if the FHR was<56 bpm. Digoxin and/or intravenous immune globulin (IVIG) was added for progressive fetal heart failure. Third, we delivered fetuses by cesarean section for specific indications that included abnormal BPS, maternal/fetal conditions, progression of heart failure, or term pregnancy. We assessed perinatal survival, predictors of delivery and maternal/fetal complications in 29 fetuses with 3° (n=23) or 2° (n=6) AV block. There were no fetal deaths. In utero therapy included dexamethasone (n=29), terbutaline (n=13), digoxin (n=3) and/or IVIG (n=1). Delivery indications included term gestation (66%), fetal/maternal condition (14%), low BPS (10%) and progression of fetal heart failure (10%). An abnormal BPS correlated with urgent delivery.

Conclusion: These results suggest that applying this specific management strategy that begins in utero can improve perinatal outcome of immune-mediated AV block.