NASHVILLE, TENN – Women with multiple sclerosis who fare poorly on specific medications before pregnancy don’t tend to do any better afterward, a new study finds. This suggests that pregnancy – a period when many women with MS stop taking their medication – should trigger discussions about switching from drugs that aren’t doing the job, the study’s lead author said.
“It’s a good time to consider the therapy that the individual is on, whether it’s one that’s effective for them, and whether it’s one they should return to when they start up therapy post-partum. It’s likely it will affect them the same way” after pregnancy as before, Caila Vaughn, MPH, PhD, of the University of Buffalo, said in an interview at the 2018 annual meeting of the Consortium of Multiple Sclerosis Clinics.
From 2012-2017, the study authors sent surveys to 1,651 women in the New York State Multiple Sclerosis Consortium as part of an effort to understand how pregnancy affects women with MS, especially when relapses return in the post-partum period.
Of the 1,651 women, 635 (38% of the total) agreed to answer questions about their reproductive history.
Pregnancy data was available for 627 patients of whom 490 (78%) had been pregnant. Of those, 109 said they became pregnant after their MS diagnosis.
Fifty-three (49%) reported relapses in the 2 years prior to pregnancy and 46% reported them in the 2 subsequent years. Just 12% reported relapses during pregnancy, and 16% said they took disease-modifying drugs during pregnancy (60% had taken them before pregnancy).
Why does MS become less severe during pregnancy? “We believe the dormancy of the disease is related to an immune system that is naturally decreased and depressed during pregnancy,” Dr. Vaughn said. Afterward, she said, “the relapses are related to the recovery of the immune system post-partum.”