Azathioprine during pregnancy

• Pregnancy and lactation - limited data suggests that if a woman becomes pregnant while taking a thiopurine for inflammatory bowel disease, continuing treatment does not increase the risks of pregnancy complications or congenital abnormalities. However, it seems prudent not to start a thiopurine if a woman plans to become, or is, pregnant, nor should women breast feed- while taking a thiopurine (1).
• there is evidence suggestive of an increased risk of congenital abnormalilty and spontaneous abortion if the father has received treatment with a thiopurine within 3 months of the baby being conceived (2)

Reference:

1. Drugs and Therapeutics Bulletin (2002), 39 (12), 91-95.
2. Rajapske RO et al (2000). Outcomes of pregnancies when fathers are treated with 6-mercaptopurine for inflammatory bowel disease. Am J Gastroenterol, 95, 292-7.