Umbilical Cord Bilirubin as a Predictor of Neonatal Jaundice in Babies with ABO Blood Group Incompatibility versus without Incompatibility

Introduction: Severe hyperbilirubinaemia cause long-term morbidity that can be prevented by early prediction of the development of significant jaundice by measuring Umbilical Cord Bilirubin (UCB). Aim: To measure the predictability of UCB as an early marker of development of significant hyperbilirubinaemia needing phototherapy.Materials and Methods:The study was a prospective observational study conducted at Vinayaka Mission Medical College, Karaikal, Pondicherry, India. A total of 50 babies born between February and August 2022 were included in the study. Bilirubin levels were obtained at birth by umbilical cord sampling and rechecked again at third or fourth day. Blood group incompatibility was defined as A or B blood group babies born to O group mothers. Phototherapy was started when the bilirubin levels were above or upto 2 mg/ dL below the cut-off for that patient as indicated by the curve for the risk group of the patient as per the American Academy of Paediatrics (AAP) guidelines. Phototherapy also was started if clinically indicated by visual assessment by Kramers rule.Results: Results were analysed by Receiver Operating Characteristics (ROC) curve analysis for measurement of sensitivity and specificity for predicting significant neonatal hyperbilirubinaemia. ROC curve anlaysis revealed that a cut-off of UCB of 1.95 mg/dL resulted in an accepatable sensitivity and specificity for predicting significant jaundice requiring phototherapy at 75% and 68% respectively. ROC curve analysis revealed that Area Under Curve (AUC) for UCB levels of all babies for predicting jaundice requiring treatment was 0.765, 95% CI 0.592 to 0.937. Separate ROC analysis showed that AUC for UCB for predicting phototherapy in babies with blood group incompatibility (AUC 0.80, 95% CI 0.418 to 1.00) was more significant than the AUC for babies without blood group incompatibility (AUC 0.490, 95% CI 0.29 to 0.69).Conclusion: UCB has high predictability for significant jaundice requiring phototherapy. The prediction is more when babies with blood group incompatibility is considered compared to babies without blood group incompatibility.