Maternal steroid therapy for fetuses with immune-mediated complete atrioventricular block: a systematic review and meta-analysis

Introduction: To explore the effect of maternal fluorinated steroid therapy on fetuses affected by immune-mediated complete atrio-ventricular block (CAVB) in utero.Material and methods: Pubmed, Embase, Cinahl, and ClinicalTrials.gov databases were searched. Only studies reporting the outcome of fetuses with immune CAVB diagnosed on prenatal ultrasound without any cardiac malformations and treated with fluorinated steroids compared to those not treated were included. The primary outcome observed was the regression of CAVB; secondary outcomes were need for pacemaker insertion, overall mortality, defined as the occurrence of either intrauterine (IUD) or neonatal (NND) death, IUD, NND, termination of pregnancy (TOP). Furthermore, we assessed the occurrence of all these outcomes in hydropic fetuses compared to those without hydrops at diagnosis. Meta-analyses of proportions using random effect model and meta-analyses using individual data random-effect logistic regression were used to combine data.Results: Eight studies (162 fetuses) were included. The rate of regression was 3.0% (95%CI 0.2-9.1) in fetuses treated and 4.3% (95%CI 0.4-11.8) in those not treated, with no difference between the two groups (odds ratio (OR): 0.9, 95%CI 0.1-15.1). Pacemaker at birth was required in 71.5% (95%CI 56.0-84.7) of fetuses-treated and 57.8% (95%CI 40.3-74.3) of those not treated (OR: 9, 95%CI 0.4-3.4). There was no difference in the overall mortality rate (OR: 0.5, 95%CI 0.9-2.7) between the two groups; in hydropic fetuses, mortality occurred in 76.2% (95%CI 48.0-95.5) of the treated and in 23.8% (95%CI 1.2-62.3) of the untreated group, while in those without hydrops the corresponding figures were 8.9% (95%CI 2.0-20.3) and 12% (95%CI 8.7-42.2), respectively. Improvement or resolution of hydrops during pregnancy occurred in 76.2% (95%CI 48.0-95.5) of cases treated and in 23.3% (95%CI 1.2-62.3) of those nontreated with fluorinated steroids.Conclusions: The findings from this systematic review do not suggest a potential positive contribution of antenatal steroid therapy in improving the outcome of fetuses with immune CAVB.