Objective: To compare intervention with fluorinated glucocorticoids to the natural history of untreated congenital heart block (CHB) with respect to conduction abnormalities, associated effusions, ascites, and hydrops fetalis, and the requirement for a pacemaker.
Methods: Records of all mothers enrolled in the Research Registry for Neonatal Lupus were reviewed. The cohort includes 47 mothers whose sera contain anti-SSA/Ro or anti-SSB/La antibodies, and their 50 offspring with CHB, in whom at least 4 echocardiograms were performed after in utero diagnosis. In 28 pregnancies, mothers received dexamethasone 4-9 mg/day for 3-19 weeks or betamethasone 12-24 mg/week for >6 weeks (group A). In 22 pregnancies, fluorinated steroids were not used (group B).
Results: Third-degree block was present in 21 fetuses in group A and 18 fetuses in group B; none were reversible despite steroid treatment. Three fetuses in group A and 2 in group B progressed from second-degree block, alternating with third-degree block, to permanent third-degree block at birth and postnatally. Of 4 fetuses in group A with second-degree block at presentation, all reverted to first-degree block by birth; 2 remain so at age 4 years, 1 alternates between first-degree and second-degree block at 2 years, and the fourth is in second-degree block at age 4 years. Of 2 fetuses in group B with second-degree block at presentation, both progressed to permanent third-degree block postnatally. Initial echocardiographic evaluation revealed pericardial effusions in 13 group A versus 4 group B fetuses, pleural effusions in 2 group A versus 0 group B, ascites in 8 group A versus 0 group B (P < 0.007), hydrops fetalis in 8 group A versus 0 group B (P < 0.007), and intrauterine growth restriction in 1 group A versus 1 group B. Pericardial effusions resolved and reappeared in both groups. Steroid therapy was most effective in the resolution of pleural effusions (2 of 2), ascites (6 of 8), and hydrops fetalis (5 of 8). Oligohydramnios ensued in 9 group A and 2 group B fetuses. Although fetuses in group A had more complications at presentation than those in group B, there were no significant differences in the duration of pregnancy (35.7 weeks versus 37.0 weeks), the number of deaths (4 versus 1), final degree of heart block, or requirement for a pacemaker (14 versus 11).
Conclusion: While prospective trials are needed, these data suggest that fluorinated steroids should be considered for fetuses with incomplete block or hydropic changes. Serial echocardiograms are recommended to monitor fetal progress. It remains to be determined whether third-degree block is reversible if therapy is initiated immediately upon detection.