Association between maternal anti-Ro and anti-La antibody levels and congenital heart block: a 20-year cohort study

To evaluate the association between maternal anti-Ro and anti-La antibody levels and the occurrence of congenital heart block (CHB) in fetuses and newborns. This retrospective cohort study included 182 pregnant women with positive anti-Ro and/or anti-La antibodies who received prenatal care at our tertiary center between 2002 and 2022. Maternal clinical, laboratory, and obstetric variables were analyzed. Thirteen fetuses (7.1%) were diagnosed with CHB. Mothers of affected fetuses had significantly higher anti-Ro (median 240 vs. 42; p < 0.001) and anti-La (median 150 vs. 10; p < 0.001) levels. Anti-La positivity was more frequent in the CHB group (76.9% vs. 42.6%; p = 0.017). Lower complement C4 levels (p = 0.008) and disease duration of less than 1 year since diagnosis (p = 0.008) were also associated with CHB. Preconception hydroxychloroquine and prednisone use were less frequent in affected pregnancies (p = 0.044 and p = 0.039, respectively). Higher maternal anti-Ro and anti-La antibody levels were significantly associated with fetal CHB. Preconception hydroxychloroquine may provide a protective effect. Early diagnosis and specialized care are essential for optimizing neonatal outcomes.