Antenatal phenobarbital for reducing neonatal jaundice after red cell isoimmunization

Thomas JT, Muller P, Wilkinson CS

Summary

Antenatal phenobarbital for reducing neonatal jaundice after red cell isoimmunization

Inadequate evidence on antenatal use of phenobarbital for reducing jaundice in babies born to mothers whose blood is incompatible with the baby's blood.

The mothers and baby's bloods do not normally mix during pregnancy. However, occasionally there can be a small leak from the baby to the mother, and this happens more often during labour and birth than during pregnancy. When the mother's and the baby's red cells are incompatible, and if the leak is large enough, the baby's cells can stimulate the production of antibodies in the mother, and the mother becomes sensitized (isoimmunized). In a subsequent pregnancy, if again the mother's and the baby's red cells are incompatible, the baby's red cells can be destroyed as the mother's antibodies cross the placenta and attack the baby's blood cells. The baby's liver can have trouble coping with the byproduct (bilirubin) of the red cell destruction, resulting in anaemia and jaundice. Since phenobarbital improves the function of the liver, giving it to mothers just before birth may reduce the amount of bilirubin in the baby and thus reduce jaundice. This decreases the need for phototherapy and need for blood transfusion for the baby. This drug has some minor side effects which need to be assessed. The review of trials found no randomised controlled trials of antenatal phenobarbital in isoimmunized mothers.