A management strategy for fetal immune-mediated atrioventricular block

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

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.

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