Background: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system usually diagnosed in young adults, therefore frequently affects women of childbearing age and pregnant women. Due to uncertain or worrisome data regarding fetal safety, some MS disease-modifying therapies (DMTs) are not recommended or are contraindicated during pregnancy. To date, data on the use of MS DMTs during pregnancy in real life have remained limited.
Objectives: This study aimed to assess the level and characteristics of MS DMTs use during pregnancy in France and their evolution over the period 2010-2021, and to describe changes in MS DMTs use before, during and after pregnancy.
Methods: We used data of the National Mother-Child EPI-MERES Register, built from the National Health Data System (SNDS) and covering 98% of deliveries in France since 2010. All pregnancies ended between 1 April 2010 and 31 December 2021 in women aged 15-49 years with or without MS were included. Pregnancies were considered exposed to MS DMT if at least one dispensation of a MS-specific DMT (including beta-interferon [IFNB], glatiramer acetate [GA], teriflunomide [TRF], dimethyl fumarate [DF], fingolimod [FG], natalizumab [NZ] and ocrelizumab [OC]) occurred within 30 days before pregnancy start and/or during pregnancy. Maternal and pregnancy characteristics and MS DMT exposure during pregnancy were described overall and by time sub-periods. Changes in MS DMT before, during and after pregnancy were assessed among women on MS DMT 6 months before pregnancy.
Results: Among a total of 11,891,167 pregnancies, 20,567 involved women with MS. The frequency of pregnancies with MS increased over time, from 4,378 in 04/2010-12/2012 to 5,435 in 01/2019-12/2021. Among them, the time from MS diagnosis to pregnancy onset increased (from 3 to 5 years, respectively) and the use of a second- or third-line DMT before pregnancy became more frequent (from 7.6% to 23.6%). The number of pregnancies exposed to MS DMT increased from 1,079 in 04/2010-12/2012 to 2,413 in 01/2019-12/2021. Overall, 38.8% were exposed to IFNB, 26.1% to GA, 18.1% to NZ, 9.7% to DF, 5.6% to FG, 2.5% to TRF and 1.0% to OC. Among women on MS DMT 6 months before pregnancy, 78.0% discontinued their treatment and 7.6% switched to another. DMT discontinuations and switches occurred mainly before the start of pregnancy (33.0% and 77.0%, respectively) or during the first trimester of pregnancy (58.3% and 17.8%, respectively). Most women had resumed MS treatment 6 months after pregnancy, either with the same DMT as before pregnancy (60.6%) or with a different one (18.5%).
Conclusions: Pregnancy in women with MS is becoming increasingly common, leading to important changes in therapeutic management around pregnancy.
