The impact of treatment of the fetus by maternal therapy on the fetal and postnatal outcomes for fetuses diagnosed with isolated complete atrioventricular block.

Objectives: to analyse retrospectively the data of fetuses diagnosed with isolated complete atrioventricular block and efficacy of treatment of the fetus by maternal therapy.

Materials: Between 1992 and 2004, we diagnosed complete atrioventricular block in 26 singleton and 2 twins fetuses of 27 pregnant women known to have anti Ro/La antibodies, 11 with autoimmune disease, one patient analysed in 2 pregnancies. At presentation, 20 of the fetuses were compensated and non-hydropic, while 8 had hydrops. Twenty patients were treated with dexamethasone, 2 with associated salbutamol and one mother with isoproterenol.

Results: Age at presentation was not different between the hydropic and non-hydropic fetuses. The fetuses with hydrops, however, had a lower mean heart rate at presentation, 48.5 +/- 9.25 with a range from 32 to 60, compared to 59.95 +/- 7.9 beats per minute, with a range from 50 to 80, in the non-hydropic fetuses (p less than 0.002). Equally, after birth the mean heart rate in hydropic fetuses was 42.6 +/- 5.1, with a range from 38 to 50, as opposed to 56.05 +/- 11.8 beats per minute, with a range from 29 to 110, in the non-hydropic fetuses (p less than 0.015), The hydropic fetuses were delivered at 31.7 +/- 3.8 weeks' gestation, with a range from 29 to 38 weeks (p less than 0.003) compared to 35.5 weeks' gestation +/-2.04, with a range from 31 to 38, in the non-hydropic fetuses. Mortality was 37.5% in the hydropic fetuses, versus 5% of those without hydrops (p less than 0.02). Pacemakers were implanted in 22 of 26 infants born alive, at a median of 45 days, with a range from 1 day to 5 years, in those without hydrops during fetal life, and 3 days, with a range from 1 day to 8 months in those afflicted by hydrops, of whom 2 died despite the implant of the pacemaker. The presence and degree of hydrops had a significantly negative predictive value. No significant differences were observed between the treated and non treated cases, albeit that administration of steroids ameliorated rapidly the hydrops in 3 of 5 cases.

Conclusions: The outcome in our cases was mainly dependent on the presence and degree of fetal cardiac failure. Treatment of the fetus by maternal administration of steroids did not result in any regression of the conduction disorder, but had a favourable effect on fetal hydrops.