central nervous system, according to the National Multiple Sclerosis Society. The damage causes a disruption to nerve signals traveling to and from the brain, which causes the numbness, walking problems, blurry vision and fatigue.
About 85 percent of those with MS start with a relapsing-remitting course, in which attacks are followed by partial or total recovery, according to the study. More than half go on to develop a more progressive form of the disease, in which symptoms worsen over time and there are fewer, shorter periods without symptoms. Eventually, the disease can lead to loss of vision and paralysis.
Women are twice as likely to develop MS as men, though women tend to have less severe cases than men, according to the study.
About three-quarters of the women in the study had children. The researchers measured the time it took for women to reach level 6 on the Expanded Disability Status Scale (EDSS), a rating system used by doctors to describe symptoms, with level 1 being the least severe and 10 being death due to MS. Level 6 is defined as needing a cane, crutch or brace to walk.
Women who did not have children took an average of 13 to 15 years to progress to EDSS 6, while women who had children took an average of 22 to 23 years to reach that stage, the researchers found.
“Having one or more children does seem to be beneficial,” said Patricia O’Looney, director of biomedical research for the National Multiple Sclerosis Society. “But we don’t know enough about