A new study found that female participants were no more likely to have a flare-up of multiple sclerosis after receiving fertility treatments than they were before their treatments. Researchers also found a link between the use of MS medications and a lack of increase in relapses during fertility treatments.

The study by researchers at Northwestern University, in Chicago, involved 65 female participants with an average age of 37 who had at least one fertility treatment. A total of 56 had a diagnosis of MS and nine had clinically isolated syndrome, which is the first episode of MS symptoms. Overall, participants had been diagnosed for an average of eight years. None had progressive MS.

Participants had 124 cycles of fertility treatments, including in vitro fertilization and oral medications to induce ovulation. Researchers reviewed medical records to see how many relapses people had in the year before having fertility treatments and then also in the three months after each treatment.

A total of 43 percent of the participants were actively receiving disease-modifying therapy for their MS during fertility treatments, and the majority had received treatment within the year prior.

Researchers found no increase in the relapse rate after fertility treatment. The result was the same when researchers looked at specific types of fertility treatments including in vitro fertilization, egg banking for fertility preservation, embryo transfer from donor eggs, and intrauterine insemination.

Researchers concluded that being on MS treatments at time of fertility stimulation was linked to lower rates of relapse. None of the people on disease-modifying therapy relapsed in the three months post-stimulation.

The researchers also assessed if the relapse rate was affected by whether or not the fertility treatment resulted in a pregnancy, as earlier studies had suggested that could influence the relapse rate. They found that the relapse rate after a fertility treatment with no resulting pregnancy was no different than the rate prior to the treatment.

A limitation of the study was that it looked back in time. It is possible that information about relapses was not collected in all cases. In addition, confirmation of relapses via brain scans was not available in all cases.

The study was published in Neurology Neuroimmunology and Neuroinflammation.