Multiple sclerosis treatment strategies and disease activity during pregnancy and post-partum: real-world data from the Swiss MS cohort

Managing MS during pregnancy and post-partum (PP) is challenging as multiple treatment strategies exist.

Aim of this study is to describe all pregnancies observed from 2012 to 2023 in the Swiss MS cohort, including disease modifying treatments (DMTs), relapses, MRI activity and serum neurofilament light chain (sNfL) levels. Anti-CD20-monoclonal antibodies (anti-CD20) and natalizumab are defined as high-efficacy DMT (HET). Disease activity was assessed by relapse rate during pregnancy or PP, number of new/enlarging T2w lesions on the first cMRI after birth or sNfL levels during pregnancy and PP. We will compare patients continuously exposed to HET during pregnancy to patients who stopped DMT or were treatment-naive before and remained untreated during pregnancy. We will estimate odds ratios with generalized estimating equation models (GEEs) adjusted for age, disease duration, EDSS and relapse rate in the year before pregnancy. For new/enlarging T2w lesions a sensitivity analysis using Firth logistic regression will be performed. sNfL z-scores during pregnancy and PP will be compared between HET, oral DMT, platform DMT and untreated patients at blood sampling using GEEs. This study will show whether or not continuous exposure to HET during pregnancy is associated with a lower risk of disease activity compared to women who were untreated or had not been continuously exposed to HET during pregnancy.