Use of multiple sclerosis disease-modifying therapies during pregnancy in France: Nationwide study between 2010 and...

Multiple sclerosis (MS) frequently affects women of childbearing age and pregnant women.

To assess the use of MS disease-modifying therapies (DMTs) during pregnancy in France over the last decade, marked by an increasing DMTs availability.

All pregnancies ended from April 2010 to December 2021 in women with MS were identified based on the nationwide Mother-Child Register EPI-MERES, built from the French National Health Data System (Système National des Données de Santé (SNDS)).

Of a total of 20,567 pregnancies in women with MS, 7587 were exposed to DMT. The number of DMT-exposed pregnancies markedly increased from 1079 in 2010-2012 to 2413 in 2019-2021 (+124%), especially those exposed to glatiramer acetate, natalizumab, dimethyl fumarate, and anti-CD20. Among pregnancies of women on DMT 6 months before pregnancy, 78.0% underwent DMT discontinuation and 7.6% switched DMT, generally before (33.0% and 77.0%, respectively) or during the first trimester of pregnancy (58.3% and 17.8%, respectively). DMT discontinuation decreased from 84.0% in 2010-2012 to 72.4% in 2019-2021 and was less frequent among women aged ⩾35 years and those socioeconomically disadvantaged.

Despite MS therapeutic management adaptations to pregnancy, exposure during pregnancy to treatments whose safety profile has not yet been clearly established has increased sharply over the last decade.