JAMA Neurol

Can MS relapses during pregnancy be prevented with smarter medication management?

August 26, 2025

Study details: This multicenter, retrospective cohort study analyzed 6,341 pregnancies in 4,998 women with relapsing-onset multiple sclerosis (MS) using data from the French MS registry (1990–2023). Researchers applied mediation analysis and causal inference methods to assess the impact of disease-modifying therapy (DMT) management on annualized relapse rates across preconception, gestation, and postpartum periods.

Results: DMT changes during pregnancy significantly increased relapse risk, especially in patients who discontinued natalizumab early or resumed it late (causal rate ratio [cRR], 2.18) and those on fingolimod (cRR, 2.15). In contrast, the most protective strategy was anti-CD20 therapy administered 9 to 12 months before conception and resumed within three months postpartum (cRR, 0.38). Natalizumab with short interruption also showed benefit (cRR, 0.80), while interferon β (cRR, 0.93) and glatiramer acetate (cRR, 0.91) had modest effects.

Clinical impact: Careful pre-pregnancy planning of DMT, especially anti-CD20 timing, can substantially reduce relapse risk in pregnant MS patients. These findings support individualized treatment strategies to optimize maternal and fetal outcomes.

Source:

Gavoille A, et al; OFSEP Investigators. (2025, August 4). JAMA Neurol. Therapeutic Management During Pregnancy and Relapse Risk in Women With Multiple Sclerosis. https://pubmed.ncbi.nlm.nih.gov/40758347/