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Updated: Aug 5, 2026
A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data
Published on: December 9, 2015
Association between pregnancy timing and disability outcomes in women with mild relapse-onset multiple sclerosis
Jessica Shipley1, Chao Zhu2, Paul G Sanfilippo2
1Department of Neuroscience, School of Translational Medicine, Monash University, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Melbourne, VIC, Australia.
Background:
Pregnancy does not adversely affect disability outcomes in women with multiple sclerosis (MS). However, it remains uncertain whether pregnancy is associated with slower disability accumulation, and whether this association differs according to the timing of pregnancy during the disease course.
Methods:
This observational cohort study used prospectively ascertained data in the international MSBase Registry (1991-2022), supplemented with retrospective surveys detailing participants' complete pregnancy histories. The study included women with mild relapse-onset MS, defined as an Expanded Disability Status Scale (EDSS) score of 2.5 or below. A flexible parametric survival model was used to assess the time-varying effect of live-birth pregnancy on reaching sustained EDSS 3.
Results:
We included 2079 women, of whom 571 had a live-birth pregnancy after baseline. Live-birth pregnancies occurring within the first 4.42 years of follow-up were associated with longer time to sustained EDSS 3. At 10 years, live birth was associated with an absolute cumulative difference of 0.51 years in time to this disability milestone (95% confidence interval (CI): 0.23, 0.79). Among women with live births, postpartum relapses were associated with shorter time to sustained EDSS 3 (hazard ratio (HR): 1.61; 95% CI: 1.02, 2.55).
Conclusion:
Live-birth pregnancy occurring earlier in follow-up was associated with a longer time to disability accrual.
