Discordant immune complete heart block and growth restriction in dichorionic twin pregnancy with permanent pacemaker implantation of an 1140 g neonate.

Fetal atrioventricular block is a rare pathology, mostly due to placental transmission of maternal SSA/Ro and SSB/La antibodies, and can lead to severe fetal or neonatal outcomes. We report a case of dichorionic, diamniotic twin pregnancy, with maternal SSA/Ro antibodies. Isolated complete atrioventricular block was diagnosed at 23 weeks in one fetus (Twin A), while the second fetus (Twin B) remained in normal sinus rhythm. Severe asymmetric intrauterine growth restriction occurred in Twin A. Delivery was by caesarean section at 32 + 2 weeks. Neonatal permanent pacemaker was inserted on the first day after birth in 1140 g neonate. Discordant heart block in twin pregnancy has already been reported in a few dichorionic pregnancies, but the pathway of discordant disease expression remains unclear. Extraction decision is a dilemma between cardiac failure prevention and prematurity associated twin morbidity. This case shows a successful pacing in a very low birth weight neonate.