Does Paternal Exposure to Methotrexate Affect Birth Outcomes?

Methotrexate is used to treat recalcitrant psoriasis. Its teratogenic effects are unquestionable, as are its abortifacient properties. However, the potential hazards to the fetus when the father is exposed to methotrexate at the time of conception remain unclear. Because azoospermia is possible during methotrexate therapy, it has been suggested that it might be difficult for a man on methotrexate to conceive. In addition, it is unknown if methotrexate therapy might cause genotoxic effects on sperm that might translate into chromosomal abnormalities in the offspring, or whether there is methotrexate in seminal fluid that might cross the vaginal mucosa and, through the circulation, affect the unborn fetus.

To test whether paternal methotrexate…