Study finds multiple pregnancies shorten lifespan

CHICAGO (WLS) -- Saying your kids are taking years off of your life may not be a just a figure of speech anymore.

New research from Northwestern University found that having multiple pregnancies may cause a woman's cells to age more quickly.

The study, published this week in Scientific Reports, looked at two markers of cellular aging in 3,200 young women between the ages of 20-22 in the Philippines.

Researchers were surprised to find that cellular aging accelerated by between 6 months and 2 years for each additional pregnancy. Another unexpected finding was that pregnant women's cells looked younger, not older, than predicted.

While there is sufficient evidence that having more children, especially more than four or five, can increase the risk of certain diseases and shorten a woman's overall lifespan, researchers still don't really know why.

"Our study points to cellular changes during pregnancy, possibly related to adaptive changes in the mother's immune system as a possible explanation," said Christopher Kuzawa, a professor of anthropology at Northwestern. "There's still a lot we don't know. For instance, it's not clear whether these relationships will persist into later life as these women age. We also do not know whether these changes will actually lead to less favorable long-term health outcomes."