As more women are choosing to have children later in life, researchers in Oklahoma are studying how to extend the female reproductivity period.Aging biologists at the Oklahoma Medical Research Foundation discovered new clues on why women in their 30s struggle to get pregnant. Researchers said it could have something to do with immune cells and inflammation. "We don’t know if the cells around the egg are becoming inflamed, which in turn is driving the promotion of certain type of immune cells, or if the immune cells are coming into the ovary with advancing age, and that is what’s driving the inflammation," said Michael Stout, an associate professor with OMRF's Aging and Metabolism Program.Menopause signals the end of fertility, but researchers said most women's ovaries begin to age long before that, at around age 35.In 2020, nearly 19% of all pregnancies were women 35 and older, according to the Centers for Disease Control and Prevention.“In the late 30s, embryo loss has increased a lot," said Victor Isola. "The goal would be to understand why this is happening so fast and what can be done."Aside from reducing adverse pregnancy outcomes, researchers said this discovery could help slow down aging overall."There is an association between reproductive aging and aging throughout the whole body," Stout said. "If we can delay aging in the ovary, the goal would be to delay systematic aging because then we can put off diseases that reduce quality of life but are also costly from an economic system."