Pregnancy Interrupts Treatment for MS, Finds Real-World Study

Women are two to three times more likely to have multiple sclerosis (MS) than men. They tend to be younger at disease onset and have greater relapse activity. On the other hand, they have slower disability progression and develop secondary progressive MS later during the disease development than men.

Current standard of care for MS includes disease-modifying therapies (DMTs) to slow disease progression, lower relapse rate, and reduce new lesion formation. But certain factors, such as pregnancy and breastfeeding, can mean that disease-modifying therapies are not safe for woman.

These and other factors may lead to differences in treatment strategies between men and women with MS. In a retrospective study published on March 5, 2024, in the Journal of Neurology, Harald Hegen, M.D., Ph.D., from the department of neurology at the Medical University of Innsbruck in Austria, and his colleagues retrospectively analyzed data from the Austrian Multiple Sclerosis Treatment registry (AMSTR) to identify differences in treatment.

The researchers looked at records from an AMSTR dataset dated from Aug. 3, 2006, to Nov. 10, 2020. The study included 4,224 adults diagnosed with relapsing-remitting MS who had started treatment with a moderate-efficacy DMT, such as dimethyl fumarate or teriflunomide, or a high-efficacy DMT, such as Tysabri (natalizumab), Ocrevus (ocrelizumab), or Lemtrada (alemtuzumab).

The primary outcomes were time to DMT escalation (switch from a moderate-efficacy to a high-efficacy DMT), time to discontinuation of a moderate-efficacy DMT, time to DMT de-escalation (switch from a high-efficacy to a moderate-efficiency DMT), and time to discontinuation of a high-efficacy DMT. At baseline, a total of 2,792 patients had received a high-efficacy DMT, and 1,432 had received a moderate-efficacy DMT.

The researchers found that women with MS were more likely to discontinue a moderate-efficacy DMT at a younger age versus men. Women were also more likely to stop using a high-efficacy DMT than men. One of the top reasons women gave for stopping treatment with either a moderate-efficacy or a high-efficacy DMT was family planning.

The study also found sex-related differences in terms of treatment escalation. An increase in annualized relapse rate by one point was more likely to result in treatment escalation in males compared to females with MS.

The study authors emphasize the importance of awareness of intentional or unintentional differences in care in males and females with MS. They conclude, “Our study results should increase the awareness of sex-related treatment differences, thus, prevent unwarranted treatment decisions and eventually prevent further disease activity and morbidity especially in women.”