Prior pregnancy may offer protection from MS

Having been pregnant reduces the risk of developing multiple sclerosis (MS) according to a new meta-analysis of four studies. The analysis found risk is not affected by the use of oral contraceptives.

We know that MS is caused by lots of different factors, both genetic and environmental. It affects almost three times more women than men, so sex hormones could be involved in the disease’s development.

Various studies have concluded mixed results when measuring whether prior pregnancy offers protection from MS.

Researchers in Iran wanted to clarify the relationship between MS, oral contraceptives and pregnancy. They looked at four previously published studies, two conducted in the US and two in Iran.

Three of the studies analysed pregnancy history and found an overall decreased risk for the disease when a woman had had at least one pregnancy. Researchers calculated the odds of developing MS were reduced by 36% in women who had been pregnant compared with those who had not.

The analysis did not find any significant effect of oral contraceptives on MS.

The researchers said perhaps the protective effects of pregnancy could be related to a modulation of the immune system by sex hormones.