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.

Authors' conclusions: 

The use of antenatal phenobarbital to reduce neonatal jaundice in red cell isoimmunized pregnant women has not been evaluated in randomised controlled trials.

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Background: 

Neonates from isoimmunized pregnancies have increased morbidity from neonatal jaundice. The increased bilirubin from haemolysis often needs phototherapy, exchange transfusion or both after birth. Various trials in pregnant women who were not isoimmunized but had other risk factors for neonatal jaundice have shown a reduction in need for phototherapy and exchange transfusion by the use of antenatal phenobarbital. A recent retrospective case-controlled study showed reduction in the need for exchange transfusion for the neonates from isoimmunized pregnancies.

Objectives: 

To assess the effects of antenatal phenobarbital in red cell isoimmunized pregnancies in reducing the incidence of phototherapy and exchange transfusion for the neonate.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2009).

Selection criteria: 

Randomised and quasi-randomised controlled trials of pregnant women established to have red cell isoimmunization in the current pregnancy during their antenatal testing and given phenobarbital alone or in combination with other drugs before birth.

Data collection and analysis: 

All three review authors independently assessed study eligibility and quality.

Main results: 

No trials met the inclusion criteria for this review.

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