Female Reproductive Factors Do Not Modify MS Prognosis

Although women have an increased risk of multiple sclerosis (MS) compared with men, new research has shown that the onset of first menstruation, pregnancies, and breastfeeding do not substantially modify the risk of MS or disability.

The study, published in Neurology, examined reproductive information of female participants with clinically isolated syndrome (CIS), a disease course in MS. There were data on 501 participants and the authors examined the relationship of age at menarche and effect of pregnancy and breastfeeding on the risk of clinically definite MS, McDonald 2010 MS, and Expanded Disability Status Scale (EDSS) 3.0 and 6.0.

“Consistent data show that women worldwide are at higher risk for [MS], with an incidence sex ratio of 2:1, which increased over the last 2 decades,” the authors explained. “However, there is conflicting evidence on the role of sex in MS prognosis.”

The 501 patients who filled out the survey, compared with 270 women identified with MS who did not fill out the survey, were more prone to have abnormal baseline magnetic resonance imaging (82% vs 59%, P <.005), were more likely to be on disease-modifying therapy (53% vs 16%, P <.005), and had a longer follow-up (9.5 vs 5.3 years, P <.005).

The mean age of menarche was 12.5 years and the authors found that patients whose age at menarche was younger than 12.5 had a shorter time from menarche to CIS (18.5 years) compared with patients whose age at menarche was older than 12.5 years (19.7 years). Age at menarche was not related to risk of a second attack, McDonald 2010 MS (used to determine a definitive diagnosis of MS), or disability accrual.

More than half (302 patients, 60%) of participants who filled out the survey had at least 1 pregnancy before CIS or during follow-up. Pregnancy prior to CIS, which occurred in 191 (38%) of the patients, was highly protective for clinically definite MS. Pregnancy after CIS, which occurred in 142 (28%) of women, also had a protective effect for clinically definite MS.

Analyses of the women who did and did not breastfeed after CIS revealed no significant differences.

“The results of this study provide us with useful information for women with MS regarding reproductive counseling,” the authors concluded. “The main message is that the prognosis of MS will not be significantly affected by pregnancy once all other variables are considered. In this regard, the clinical activity, MRI findings, and early initiation of treatment are the most important prognostic factors that should be considered when addressing reproductive decisions.”

Reference

Zuluaga MI, Otero-Romero S, Rovira A, et al. Menarche, pregnancies, and breastfeeding do not modify long-term prognosis in multiple sclerosis. Neurology. 2019;92(13):e1507-e1516. doi: 10.1212/WNL.0000000000007178.