Menarche, oral contraceptives, pregnancy and progression of disability in relapsing onset and progressive onset multiple sclerosis.

Female gender and hormones have been associated with disease activity in multiple sclerosis (MS). We investigated age at menarche, use of oral contraceptives and pregnancy in relation to progression of disability in relapsing onset and progressive onset MS. We conducted a cross-sectional survey among individuals with MS, registered by the Flemish MS Society in Belgium. A time-to-event analysis and Cox proportional hazard regression were performed with time to Expanded Disability Status Score (EDSS) of 6 (requires a cane) as outcome measure. Hazard ratios for the time from onset and the time from birth were adjusted for age at onset and immunomodulatory treatment. Data on 973 women with definite MS were collected. In the relapsing onset group, women with at least two pregnancies had a reduced risk to reach EDSS 6 compared with nulliparous women. In the progressive onset group, later age at menarche was associated with a reduced risk to reach EDSS 6, whereas oral contraceptive use was associated with a higher risk of reaching EDSS 6. Our study corroborates the association of pregnancies with a reduced progression of disability in relapsing onset MS. In progressive onset MS, a slower progression was found in women with a later onset of menarche and a more rapid progression occurred when women reported the use of oral contraceptives.