Women have been told for years that if they don’t have children before their mid-30s, they may not be able to. But a new study from Princeton University has identified a drug that extends egg viability in worms, even when taken midway through the fertile window. This could theoretically extend women’s fertility by three to six years. The study appears in the journal Current Biology.
“One of the most important characteristics of aging is the loss of reproductive ability in mid-adulthood,” said researcher Coleen Murphy, a professor of molecular biology at the Lewis-Sigler Institute for Integrative Genomics. “As early as the mid-30s, women start to experience declines in fertility, increased rates of miscarriage and maternal age-related birth defects. All of these problems are thought to be caused by declining egg quality, rather than a lack of eggs.”
When she reviewed the literature on aging and on reproductive health about a decade ago, she discovered that this particular question—how to maintain egg quality with age—had been overlooked. In her research, her team identified a key protein in old, poor-quality worm oocytes (unfertilized eggs) called cathepsin B. When they administered a cathepsin B inhibitor midway through the fertile window—on day 3 of the worms’ adulthood, the equivalent of a woman in her early 30s—they successfully extended egg viability beyond the normal span. Worms who did not receive the treatment had abnormally small, misshapen eggs by day 7 of adulthood. Worms who did receive the inhibitor still had healthy, properly shaped eggs on day 7.
The cathepsin B inhibitor is nowhere near ready for testing in humans yet, Murphy said. “That’s not our area,” she said. “We wanted to say: This is something that could work. The idea that you could do something mid-reproduction to improve the rest of reproduction — for me, that’s a game changer.”