Anne-Louise Ponsonby, a professor at the Murdoch Children's Research Institute in Melbourne, said the study involved more than 800 women ages of 18-60, of whom nearly 300 had experienced a first episode of MS symptoms. The other women were healthy and acted as a control group, WebMD reported.
The study published in the journal Neurology, found women with at least one child had about half the risk of early MS symptoms compared to women without children, and the risk dropped with each additional child.
Women with three children had a 75 percent lower risk of early MS symptoms compared to women without children. In women with five or more children, risk of early symptoms of MS was down 94 percent.
Ponsonby said researchers were unsure why pregnancy might reduce the risk of MS, but it might have to do with how a woman's immune system adjusts so it doesn't reject the baby.