The primary objective of the study is to compare the prevalence rate of major congenital malformations (MCM) between 2 cohorts of pregnant participants with MS who are exposed to BRIUMVI® and who are unexposed to BRIUMVI®.

Inclusion Criteria:

1. For exposed cohort: Participant exposed to at least 1 dose of BRIUMVI®.
2. For unexposed cohort: Participants not exposed to BRIUMVI® at any time during the pregnancy.
3. Diagnosis of MS.
4. Currently or recently (within 1 year of pregnancy outcome) pregnant.
5. Authorization from healthcare provider to provide data to registry.

Exclusion Criteria:

1. Prior to enrollment, participant has exposure to anti-CD20 monoclonal antibodies at any time during pregnancy.
2. Occurrence of pregnancy outcome prior to first contact with the virtual research coordination center (VRCC) (retrospectively enrolled).
3. Exposure to known teratogens and/or investigational medications during pregnancy.

The study population will include pregnant participants with MS who are either exposed or not exposed to BRIUMVI®.