Multiple sclerosis (MS) is the most common cause of neurological disability, other than trauma, among young adults of reproductive age. In contrast to the past, today there is very little lag time from clinical onset to diagnosis. Disease-modifying therapies are also now available outside of clinical trials. However, there is very little evidence-based population data to help an individual with MS make informed decisions with respect to reproductive options.

The objective of this study is to develop a Canada-wide, prospective population-based registry of women with MS who are either trying to become pregnant and/or have become pregnant.

The study represents a “real-world” scenario. Women with MS are invited to participate, regardless of clinical course, therapy, disease duration, and/or disability. The methodology to develop such a registry is very complex making it imperative to understand the design and rationale when interpreting results for clinical purposes.

This paper is a comprehensive discussion of the study rationale and methodology.

The study is ongoing, with over 100 potential participants. Numerous future publications are envisioned as the study progresses. The present paper is thus designed to be the key referral paper for subsequent publications in which it will not be possible to provide the necessary detailed information on rationale and methodology.