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to TransWeb home page Azathioprine (Imuran) causes mutations in bacteria, but has been considered unlikely to cause cancer in humans. Azathioprine caused birth defects and small birth weight in animals. Studies in humans do not appear to show an increased rate of birth defects, premature deliveries, or miscarriages but small birth weight has been noted. Not enough cases have been reported to know for sure that Imuran does not cause birth defects. Since all patients receiving Imuran need to take it for a reason, it is difficult to tell if the primary disease resulted in growth retardation of the fetus, of if the Imuran had this effect.
Imuran can result in immunosuppression of the fetus but this effect has not been described well enough to know how often it occurs.
Imuran appears in breast milk in small amounts. Small studies of infants who were breastfed by mothers receiving Imuran did not find any abnormalities in blood counts or growth rates. However, the World Health Organization does not recommend breastfeeding to mothers taking Imuran.
Last modified:
11 May 2000