Correlation between Maternal Anti-E Antibody Titer and the Severity of Hemolytic Disease of the Fetus and Newborn

BACKGROUND: Hemolytic disease of the fetus and newborn (HDFN) caused by anti-E antibodies remains a clinical challenge. The correlation between maternal anti-E antibody titers and HDFN severity, particularly the critical titer threshold for severe clinical outcomes, remains unclear. This study aimed to investigate the correlation between maternal anti-E antibody titers and the severity of HDFN. METHODS: Clinical data were retrospectively collected from 55 pregnant women with anti-E antibody and their newborns (June 2020 - May 2024), including general maternal information and diagnostic findings. Anti-E antibody titers were measured, and neonatal outcomes were recorded. RESULTS: Among the 55 pregnant women, anti-E antibody titers ranged from 1:1 to 1:1,024. HDFN occurred in 56.4% (31/55) of cases. Titers ≥ 1:16 were significantly associated with higher HDFN incidence (χ2 = 14.996, p < 0.001). Neonatal indirect bilirubin levels correlated significantly with both HDFN occurrence (r = 0.589, p < 0.05) and maternal anti-E antibody titers (r = 0.657, p < 0.05). Neonatal length of hospital stay also showed a positive correlation with maternal antibody titers (r = 0.798, p < 0.05). CONCLUSIONS: A maternal anti-E titer ≥ 1:16 is a critical threshold predictive of HDFN occurrence and severity, providing a valuable marker for early risk stratification and clinical management.