Determinants of severity of neonatal hyperbilirubinaemia in ABO incompatibility in Nigeria.

The study was designed to determine factors responsible for the severe neonatal hyperbilirubinaemia sometimes found in ABO incompatibility in Nigeria. In 50 jaundiced babies who were ABO-incompatible it was found that the mean serum bilirubin level was significantly higher in outpatients than inpatients; this difference was probably due to the delay in recognizing jaundice among the outpatients and, possibly also to the slightly higher number of G-6-PD deficient babies in the same group, and their greater exposure to icterogenic agents. The results of serological studies suggest that ABO-incompatibility was responsible for neonatal jaundice in only 36% of these babies. Among the inpatients the need for exchange blood transfusion was more common in babies of mothers with immune anti-A or anti-B titres of 1:64 or more (P less than 0.001). Neonates at risk of ABO-haemolytic disease can be identified at birth by direct positive Coombs test and detection of immune anti-A or anti-B antibodies in the mother's serum.