Neonatal Outcomes of Rh-Negative Pregnancies in a Tertiary Level Neonatal Intensive Care Unit: A Prospective Study

Abstract

Background: Rhesus incompatibility is a preventable cause for severe neonatal hyperbilirubinemia, hydrops fetalis and still births. The prevalence of the Rh-negative blood group among Indian woman varies from 2% - 10%. Despite declining the incidence of Rhesus incompatibility, due to availability of anti-D immunoglobulin, and improved antenatal care of the Rh-negative pregnant woman, it still accounts for a significant proportion of neonatal hyperbilirubinemia and neuro-morbidity. The prevalence of Rh-negative women having Rh-positive neonates is 60%. Objectives: This study aimed to estimate the incidence of Rh iso-immunization and evaluate the outcomes of Rh iso-immunized neonates. Methods: This prospective observational study was conducted in a tertiary level neonatal intensive care unit, Princess Esra hospital, Deccan college of medical sciences, Hyderabad, Telangana, India. Consecutive intramural and extramural neonates admitted to neonatal intensive care unit with the Rh-negative mother’s blood group and hyperbilirubinemia were enrolled. Neonates born to Rh+ve mothers were excluded. Neonatal gestational age, birth weight, age at admission, duration of phototherapy, duration of hospitalization, neonatal examination and investigations were recorded in a predesigned, pretested performa. Results: A total of 90 neonates were born to Rh-negative mothers, of which 70% (63) had the Rh-positive blood group and 30% had the Rh-negative blood group. Of these 63 neonates, 48 (76.2%) had hyperbilirubinemia and 43 neonates (68.3%) had significant hyperbilirubinemia (total serum bilirubin > 15mg/dL). Among them, 2%, 75% and 23% were born to primi, multi and grandmutli, respectively. Also, 14.5% of the neonates were large for dates (LFD), 75% appropriate for dates (AFD) and 10.5% were small for dates (SFD). Premature and SFD neonates had higher incidence of hyperbilirubinemia. Significantly higher incidence of jaundice occurred within 72 hours of life. The mean serum bilirubin level among neonates with significant hyperbilirubinemia was 17.98 ± 1.76 (95% CI:17.43 - 18.52) while that of neonates without significant hyperbilirubinemia was 13.1 ± 0.53 (95% CI:12.47 - 13.77) with statistical significance (P < 0.0001). Maternal multiparity, direct coombs test (DCT) positivity, and abnormal neurosonogram (NSG) were important accompaniments of high serum bilirubin levels. Conclusions: Incidence of Rh-positive phenotype in neonates born to Rh-negative mothers is 70%. Incidence of hyperbilirubinemia among them is 76.2% and that of significant hyperbilirubinemia was 68.3%. The incidence of DCT positivity was 20.9%. Maternal multiparity, positive DCT and abnormal NSG were important associates of high serum bilirubin levels.