During pregnancy and the disease-modifying treatment (DMT)-free postpartum period, serum neurofilament-light (sNfL) levels were augmented [1]. This increase was independent of relapses, suggesting increased subclinical disease activity during this time span. Women on DMT had lower NfL during pregnancy. sNfL may qualify as a sensitive and minimally-invasive measure of disease activity during pregnancy.

These were the main results of a study that was presented as late-breaking abstract. Dr Özgür Yaldizli (University Hospital Basel, Switzerland) explained the study’s various objectives: to describe DMT use before, during, and after pregnancy in the Swiss MS cohort study (SMCS); to assess the potential of sNfL as a marker of disease activity during and after pregnancy; and to evaluate whether interrupting DMT use due to pregnancy leads to increased NfL levels in MS.

A total of 72 pregnancies in 63 relapsing MS patients were evaluated; 13 early terminated pregnancies in 10 patients were excluded. Median age was 31.4 years; median disease duration 7.1 years; median Expanded Disability Status Scale (EDSS) score 1.5 at last visit before giving birth; and median follow-up 6 years. Of 433 included samples, 167 were taken before pregnancy, 92 during pregnancy/DMT-free postpartum, and 174 after pregnancy. Most patients (n=39) were treated with fingolimod or natalizumab as last medication before giving birth; 4 patients used no DMT before, during, and after pregnancy. In 14 of 72 pregnancies, women were exposed to DMT >6 months during pregnancy (6 rituximab/ocrelizumab, 4 natalizumab, 1 interferon-beta 1a, 1 fingolimod, and 1 glatiramer acetate). In 39 pregnancies, women were exposed to DMT in the first two trimesters; in 15 pregnancies, women discontinued treatment before getting pregnant.

Relapses were more likely in the first trimester and the first 3 months postpartum. NfL levels increased towards the last trimester and in the first 3 months postpartum, not only in women who relapsed. Mean NfL levels were 22% higher during pregnancy (β=1.22; P<0.001). During the postpartum, 29 relapses occurred. Relapses were associated with 98% higher NfL levels (β=1.98; P<0.001). Mean NfL was 13% higher during the postpartum (β=1.13; P=0.009). However, this difference lost significance after including DMT exposure into the model (β=1.07; P=0.178), indicating that women on DMT had lower NfL during pregnancy. Dr Yaldizli concluded that strategies allowing to continue DMT during pregnancy may be warranted.


  1. Yaldizli Ö. MSVIRTUAL2020, Abstract LB01.06.