NAFTNet retrospective report on the treatment of anti-Ro/SSA mediated fetal heart block with dexamethasone

Abstract

Background: Complete atrioventricular block (CAVB) is a complication of maternal antibody positivity and treatment of fetal disease is controversial in terms of efficacy and safety. We hypothesized that dexamethasone treatment for fetal anti-Ro/SSA antibody-mediated cardiac disease leads to better pregnancy outcomes than expectant management. Methods: A retrospective multi-center cohort study of anti-Ro/SSA antibody positive pregnancies with fetal conduction disease reported by participating North American Fetal Therapy Network (NAFTNet) centers between January 2010 and December 2018. The primary outcomes included: fetal death, oligohydramnios, growth restriction, preterm delivery, and new maternal comorbidities. Secondary outcomes included: pacemaker prior to 28 days, transplantation, and neonatal death in maternal/fetal dyads treated with dexamethasone versus not. Results: In 127 anti-Ro/SSA positive pregnancies, 98 were treated with dexamethasone and 29 were not. Of those treated, 61/96 (63.5%) met the primary outcome including 45/91 (49.4%) premature deliveries; 20 mothers developed comorbidities during treatment (fetal death 5, 10 growth restriction, 14 oligohydramnios, two new/worsening gestational diabetes). In the untreated group, 15/25 (60%) met the primary outcome including 11/22 (50%) premature deliveries and four mothers developing comorbidities during their pregnancy (fetal death 3, one growth restriction, one new onset maternal hypertension). Regarding secondary outcomes, 37/96 (43%) treated fetuses required a pacemaker or died by 28 days, while untreated 13/25 (52%) required pacemaker placement, died prior to 28 days or required listing for transplantation. Excluding terminations, survival without transplant was 17 (68%) in untreated and 85 (89%) in treated patients (p