Past pregnancies linked to reduced MS risk in women

Women who have multiple pregnancies may have a lower risk of developing multiple sclerosis (MS), according to research published in the March 7, 2012, online issue of Neurology, the medical journal of the American Academy of Neurology.

"In our study, the risk went down with each pregnancy and the benefit was permanent," said study author Anne-Louise Ponsonby, PhD, of Murdoch Children's Research Institute in Melbourne, Australia.

Researchers reviewed information about 282 Australian men and women between the ages of 18 and 59 who had a first diagnosis of central nervous demyelination, which means they had their first symptoms similar to MS but had not yet been diagnosed with the disease. They were compared to 542 men and women with no MS symptoms. For women, the number of pregnancies lasting at least 20 weeks and the number of live births were recorded. For men, the number of children born was recorded.

The study found that women who were pregnant two or more times had a quarter of the risk of developing MS symptoms and women who had five or more pregnancies had one-twentieth the risk of developing symptoms than women who were never pregnant. There was no association between the amount of children and risk of MS symptoms in men.

"The rate of MS cases has been increasing in women over the last few decades, and our research suggests that this may be due to mothers having children later in life and having fewer children than they have in past years," said Ponsonby.