Pregnancy and Risk for Multiple Sclerosis

The multiple sclerosis (MS) relapse rate is reduced during pregnancy, but the role of parity in MS risk has not been established. Now, investigators have evaluated whether multiple pregnancies were associated with lower risk for a first clinical diagnosis of central nervous system (CNS) demyelination in a multicenter, case-control study in Australia. During a 3-year period, the authors identified 282 confirmed cases of newly diagnosed demyelinating disease. Controls were 542 individuals randomly selected from a public registry, matched 1:2 to case patients for age, sex, and region. The investigators recorded the number of prior pregnancies >20 weeks' duration and live births. Participants completed detailed questionnaires and provided serum…