Is perinatal asphyxia associated with an increase in serum bilirubin in neonates? A case-control study

OBJECTIVE: Perinatal asphyxia affects different organs of body depending upon the severity of hypoxemia and ischemia. This study was carried out to evaluate severity of hyperbilirubinemia in relation to severity of asphyxia. STUDY DESIGN: A case-control study. METHODOLOGY: Asphyxiated newborns with Apgar score ≤7 at 1 min. and categorized as severe birth asphyxia according to the WHO classification of diseases (ICD10) were matched with controls without birth asphyxia. All babies were examined twice daily for dermal icterus until start of phototherapy. Babies with congenital heart disease, sepsis, cephalohematoma, blood group incompatibility were excluded. Arterial blood gas analysis was done along with serial TSB measurement as per standard guidelines. RESULTS: 50 cases and 50 matched controls were enrolled. The average birth weight and gestation in cases was 2427 ± 30.05 g and 35.9 ± 2.5 weeks and among control it was 2633 ± 378.62 g and 37.76 ± 0.116 weeks. Among cases, onset of jaundice was 56.64 ± 20.43 h compared to 63.36 ± 23 h in control group. In the cases, the average pH was 7.31 ± 0.06, CO(2) was 41.52 ± 84, O(2) was 94.98 ± 14.83, and HCO(3) was 18.56 ± 2.04. The rise and peak of serum bilirubin differed between the case and control groups; in the cases, the peak occurred at the 22(nd) h of life, then plateaued from the 40(th) to the 78(th) hour of life, and ultimately fell at the 96(th) hour of life. In comparison, the rise and peak of serum bilirubin occurred comparatively late in the control group. The rise and peak in the control group occurred at the 80(th) and 96(th) h of life, respectively. The multiple linear regression analysis showed CRP, Apgar at 5 min. below 7 and male gender significantly affects the rise of serum bilirubin (P < 0.05). CONCLUSION: The peak serum bilirubin in asphyxiated newborns occurs earlier, and plateau for longer duration compared to normal newborns. Low Apgar at 5 min. has significant correlation to earlier rise of bilirubin.