Low risk for adverse birth outcomes in children of fathers taking AZA/6-MP before conception
Children fathered by men exposed to azathioprine and 6-mercaptopurine within 3 months before conception had no significantly increased risk for adverse birth outcomes, according to the results of a large national cohort study performed in Denmark.
“This is the largest and most comprehensive study to date on the effect of preconceptual use of AZA/6-MP in men on birth outcomes, and overall, our results are reassuring,” Sonia Friedman, MD, and colleagues from the University of Southern Denmark and Brigham and Women’s Hospital, Harvard Medical School, wrote.

Sonia Friedman
Friedman and colleagues used Danish national registries to evaluate data on singletons born from 1997 through 2013. The “exposed cohort” included 699 children who were fathered by men who were exposed to AZA/6-MP within 3 months before conception, and the “unexposed cohort” included 1,012,624 children whose fathers were not exposed within 3 months before conception. Researchers evaluated for congenital abnormalities, preterm birth and small birth weight for gestational age, adjusting for a number of potential confounders, and also performed a subgroup analysis of only men with IBD (73.5% of the exposed cohort, 0.6% of the unexposed cohort).
There were no significantly increased risks for any of these outcomes in the exposed cohort compared with the unexposed cohort in both the overall and the IBD subgroup analysis. However, the risk for small birth weight for gestational age was nonsignificantly increased in the overall analysis (adjusted OR = 1.38; 95% CI, 0.76-2.51) and in the IBD subgroup analysis (aOR = 1.45; 95% CI, 0.73-2.91), and the risk for preterm birth was also nonsignificantly increased in the IBD subgroup (aOR = 1.35; 95% CI, 0.74-2.46).
“This nationwide study has the greatest number of exposed patients to date, and since the results are reassuring, [men with inflammatory bowel disease] wishing to conceive should be advised to continue their medications,” the researchers wrote. – by Adam Leitenberger
Disclosures: The researchers report no relevant financial disclosures.