VIENNA (FRONTLINE MEDICAL NEWS) – The use of classic systemic immunosuppressive agents by men in the months shortly before conception was not associated with increased risk of low birthweight, preterm birth, or congenital anomalies in their offspring in a large Danish national registry.

“We didn’t see any real safety signals,” Dr. Alexander Egeberg reported at the annual congress of the European Academy of Dermatology and Venereology.

He and his coinvestigators at the University of Copenhagen decided to examine this issue for a simple reason: “We know quite a lot from registry studies about the safety of these drugs when used by women during pregnancy, but very little about the safety of paternal use,” Dr. Egeberg explained.

Methotrexate, azathioprine, and cyclosporine are often prescribed for patients with moderate to severe psoriasis and psoriatic arthritis as well as other chronic inflammatory disorders. Female patients are typically told to stop using these medications if they’re trying to become pregnant, or as soon as they think they might be pregnant, but nearly half of all pregnancies are unintended.

Using linked comprehensive national Danish databases, the investigators scrutinized the medical records of all children born in Denmark during 2004-2010, as well as those of their parents. They identified 2,235 children whose fathers had been on immunosuppressive therapy for a medical condition at any time prior to conception. There were 1,246 fathers who had been on azathioprine, 848 on methotrexate, and 141 on cyclosporine.

Rates of preterm birth, congenital anomalies, and low birthweight were compared in children born to fathers using immunosuppression and in 415,589 children born to fathers with no history of exposure to the medications. These comparisons entailed multivariate regression analyses adjusted for maternal age, parity, smoking status, and the child’s gender. Dr. Egeberg and his colleagues also compared rates of these reproductive complications in the subgroup of children whose fathers had been on the medications within 3 months prior to the estimated time of conception and in children whose fathers had stopped taking the drugs by that point.

None of the adverse neonatal outcomes were significantly increased in ever or recent paternal users of the medications under study, with one exception. Paternal use of cyclosporine within the last 3 months prior to conception was associated with an adjusted 3.7-fold increased likelihood of having a baby with a congenital anomaly. Dr. Egeberg, however, was quick to state that this finding was based on small numbers of exposures: 18 paternal exposures and four affected offspring.

“The cyclosporine finding should be interpreted quite cautiously,” he emphasized.

The reproductive outcomes study was supported by Danish governmental research funds. Dr. Egeberg reported having received research funding from and serving as a consultant to Pfizer and Eli Lilly.