PATERNAL USE OF METHOTREXATE

Methotrexate (MTX) is a folic acid antagonist used in the treatment of some cancers, as well as rheumatoid arthritis and severe psoriasis.

Hypothetical concerns have been raised that due to its effects on DNA replication, use of MTX in males could cause genetic abnormalities in sperm. This could potentially affect offspring conceived during ongoing use or within one sperm cycle (~74 days) of cessation. However, the available pregnancy outcome data relating to offspring conceived following periconceptual paternal MTX use do not raise concerns of increased risks of congenital malformation or other adverse outcomes. Available data are limited to around 400 exposures and ongoing data capture is therefore important.

The manufacturers of MTX advise that couples, where the male partner is undergoing or has recently completed MTX treatment, use reliable contraception and wait six months after cessation of treatment before attempting conception. Since there is no conclusive evidence of adverse fetal effects relating to paternal use, UKTIS recommends that where a couple wishes to attempt conception and the male partner’s condition is well-controlled with MTX, an assessment and discussion of the potential benefits and risks of continuing paternal treatment vs. discontinuation should be undertaken. The risks to the fetus are theoretical rather than established.

Paternal MTX use at the time of conception is not an indication for additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.