Inclusion Criteria:  Age greater than 18 years at the index date (date of pregnancy onset) of data collection, RRMS according to McDonald's 2017 criteria (Thompson et al., 2018) Affiliated person or beneficiary of a social security scheme. followed up at one of the participating centers (OFSEP centers) NTZ exposure during pregnancy according to 3 pre-defined sub-groups: continuation of NTZ throughout pregnancy and postpartum (Group 1), exposure during the first trimester (Group 2) exposure during the first and the second trimester (Group 3). Participants capable of expressing non objection French-speaking, without comprehension disorders  Exclusion Criteria:  Patient concerned by articles L 1121-5 to L 1121-8 (persons deprived of their liberty by a judicial or administrative decision, minors, persons of legal age who are the object of a legal protection measure or unable to express their consent)