Cord Blood Bilirubin as an Early Marker of Hyperbilirubinemia in Term and Late Preterm Newborns at 48 Hours of Life: A Prospective Cohort Study

Abstract

Introduction: Jaundice is a common clinical condition present during the neonatal period, which can be either physiological or pathological. Early discharge of newborns is a common practice in our country due to medico-social and economic reasons, making post-discharge follow-up of infants challenging compared to developed countries. Aim: To determine the correlation between cord blood bilirubin levels and the occurrence of hyperbilirubinemia at 48 hours of life in newborns with a gestational age of ≥35 weeks. Materials and Methods: This cohort study was conducted in the Department of Pediatrics at Dr SMCSI Medical College, Karakonam, Trivandrum, Kerala, India, over a one-year period from June 2017 to June 2018. The exposure variables included the mother’s blood group, baby's blood group, mode of delivery, gestational age, gender, and weight of the baby. The outcome variables included cord blood and 48-hour serum total and direct bilirubin levels. The data was coded and entered into Microsoft Excel and analysed using Statistical Package for Social Science (SPSS) version 16.0. Descriptive measures were calculated, and the correlation between cord and 48- hour bilirubin levels was assessed using Pearson's correlation coefficient formula. Other statistical tests applied were chisquare test and independent t-test. Results: Total subjects of 500 (243 female and 257 were males) participants were included in the study.Among the 21 babies who underwent phototherapy, 11 were female and 10 were male, and 15 were full term and six were late preterm for their gestational age . Of the 21 babies needing phototherapy, 15 were delivered by normal vaginal delivery, and six were delivered by LSCS. Correlation between cord blood bilirubin and serum bilirubin at 48hr is 0.477 with a p-value <0.001; which indicates mild correlation between the cord blood Total Bilirubin (TB)and serum TB. A cord TB value of 1.45 mg/dL had a sensitivity of 95.2% and specificity of 32.5%. A value of 1.55 mg/dL had a sensitivity of 90.5% and specificity of 40.9%. A cord TB value of 1.65 mg/dL had a sensitivity of 66.7% and specificity of 53.9%. These findings suggest that cord bilirubin levels can be used to predict which babies require further evaluation and treatment. Conclusions: Cord blood serum bilirubin can serve as a useful screening test for predicting neonatal hyperbilirubinemia and ensuring safe post-natal hospital discharge.