Parity and disability progression in relapsing-remitting multiple sclerosis

Aim It is unclear whether parity and increasing parity are risk factors for long-term disability progression in relapsing-remitting multiple sclerosis. Furthermore, data on the effects of immunomodulatory treatments in this context are limited. Objectives To examine the association between parity and long-term neurological sequela among relapsing-remitting multiple sclerosis patients. Methods A cohort study including all women with relapsing-remitting multiple sclerosis in Israel registered in Sheba Medical Center Multiple Sclerosis data registry from 1995 to 2018. The risks of progression to moderate and severe disability according to parity after disease onset were evaluated. Cox regression models using childbirth as a time-dependent covariate were used to study the association between parity and disability progression. Results During the 26,785 person-years of follow-up a total of 2281 women were included in the study. Parity was associated with decreased risk of progression to moderate (adj.HR, 0.68; 95% CI 0.54-0.85,P = 0.001) but not to severe disability (adj.HR, 0.88; 95% CI 0.68-1.14,P = 0.36). Hazard ratios for progression to moderate and severe disability were comparable between women with one, two, and three or more births. In a subgroup analysis of women who gave birth within 5 years of disease onset, immunomodulatory treatment did not affect moderate or severe disability-free survival. Conclusion This study suggests that childbirth after the onset of multiple sclerosis is associated with a decreased risk of progression to moderate neurological disability.