Objective: To evaluate the incidence of electrocardiographic and laboratory abnormalities in neonates born from mothers with connective tissue disease and positive for anti-SSA/Ro antibodies.
Study design: Electrocardiogram, blood cell counts, liver and renal function tests prospectively obtained from 51 infants born from anti-SSA/Ro-positive mothers with connective tissue disease were compared with those obtained from 50 control infants born from mothers with anti-extractable nuclear antigen (ENA)-negative connective tissue disease. One infant with congenital complete heart block was excluded from analysis.
Results: No infant showed sinus bradycardia. A first-degree atrioventricular block at birth was observed in five study group and no control group infants, P=0.023. Atrioventricular blocks spontaneously reverted or remained stable during the first year of life. Mean corrected QT value of infants born from anti-SSA/Ro-positive mothers was slightly prolonged as compared with the control group (0.404+/-0.03 s vs 0.395+/-0.02 s; P=0.060).
Conclusions: Infants exposed to anti-SSA/Ro antibodies had a significantly higher prevalence of first-degree atrioventricular block. At variance with previous studies, we observed a low frequency of hematologic abnormalities and no cases of hepatobiliary disease.