Study Finds No Heightened Relapse Risk for Postpartum Women with MS

Annette Langer-Gould, MD, PhD

Two decades ago, before the availability of disease-modifying therapies, pregnant women with multiple sclerosis (MS) were found to face significantly higher risks of relapse in the months following pregnancy.

Since then, the world of MS care has changed vastly, with new therapies and better technology to quickly diagnose MS. Those advances led a team of investigators from Kaiser Permanente to pose the question of whether the conventional wisdom about MS and pregnancy should change, too.

The investigators looked at 466 pregnancies among 375 women with MS who received care at Kaiser Permanente’s Southern California and Northern California facilities between the years 2008 - 2016. Only patients who had complete electronic health records were included in the study. EHR data were coupled with survey responses from interviews with patients.

The news was good: the data showed no rebound effect after pregnancy for women with MS.

“This shows us that women with MS today can have children, breastfeed, and resume their treatment without experiencing an increased risk of relapses during the postpartum period,” first author Annette Langer-Gould, MD, PhD, of Kaiser Permanente Southern California, said in a statement.

Langer-Gould did not respond to a request for comment at the time of publication.

The findings were released this month ahead of the American Academy of Neurology (AAN) 71st Annual Meeting in Philadelphia, PA, in May, and the study will be presented at the conference.

Nearly 1 in 4 women in the study (38%) were not on any treatment in the year prior to their pregnancy. Meanwhile, 14.6% of patients had clinically isolated syndrome, the first neurological episode for patients developing MS. Eight percent of women in the study relapsed during pregnancy.

When investigators calculated annualized relapse rates (ARRs), they found a rate of 0.39 for the year prior to pregnancy, a 0.14 ARR during pregnancy, and a 0.27 rate in the first 3 months post-pregnancy. Between the fourth and sixth months post-pregnancy, the ARR returned to pre-pregnancy levels.

The investigators found patients who exclusively breastfed their babies had lower rates of relapse. Specifically, women who breastfed exclusively for at least 2 months had a 40% lower rate of relapse compared to women who did not breastfeed. Resuming modestly effective disease-modifying therapies (DMTs) did not have a statistically significant impact on relapse rates.

In the study, 87% of enrollees breastfed during the first postpartum year, and 35% breastfed exclusively. Forty-one percent of patients resumed DMTs during the first year after pregnancy.

As for the apparent lower risk of relapse after pregnancy, the investigators suggested in could have to do with the study population, which included women who were diagnosed after only one relapse, and a higher proportion of women who breastfed exclusively compared to the general public.

Langer-Gould also noted that the study included only a small number of patients who had been treated with natalizumab or fingolimod. She told AAN that patients on those medications tend to have more severe symptoms. The small number of patients on those drugs meant investigators was unable to quantify what risks, if any, are faced by women who stop those drugs in order to get pregnant.