Postnatal phenobarbitone for preventing hyperbilirubinaemia in newborns with ABO incompatibility.

Phenobarbitone acts as an inducer of hepatic enzymes resulting in accelerated uptake, conjugation and excretion of bilirubin.'> Its prophylactic use in a high risk setting such as ABO incompatibility may help in reducing the need for phototherapy and exchange transfusions. From May to December 1998, a prospective study was done at the Neonatal Intensive Care Unit, St John's Medical College and Hospital, Bangalore. All babies with a birth weight >2000 g and gestation >35 weeks were included in the study. Babies with Rh incompatibility and perinatal asphyxia were excluded from the study. The blood group of babies born to '0' group mothers was determined and those with either 'A' or 'B' blood group were included in the study. Consent was obtained from the parents and the babies were randomized to either the treatment or the control group. The treatment group received oral phenobarbitone within 24 hours of birth in a dose of 3 mg/kg/day for the first 5 days. All the babies were assessed clinically for jaundice at 12-hourly intervals and the serum bilirubin levels were done at 24, 72 and 120 hours. Additional serum bilirubin measurements were done if the clinical examination was suggestive of hyper bilirubinaemia. Babies received phototherapy if the bilirubin level was> 15 mg/dl in the first 72 hours or> 17 mg/dl after 72 hours. An exchange transfusion was done only if the bilirubin levels were persistently >20 mg/dl. The duration of hyperbilirubinaemia (bilirubin> 15 mg/dl) and phototherapy given were recorded. Weights of the babies were recorded at birth and on day 3 to monitor for excess weight loss. Activity, sedation and other side-effects were also monitored in these babies. The Chi-square test was used for data analysis. The treatment and control groups were compared (50 babies each; Table I). The two groups were similar with regard to gestation, weight and serum bilirubin level at 24 hours after birth. None of the