As studies attempt to unearth the various causes of infertility among women, a new drug has shown promise in potentially extending women’s fertility by three to six years. Researchers at the Princeton University in the US have identified a drug that extends egg viability in worms, even when taken midway through the fertile window, thus paving the way for fertility treatments among women. “One of the most important characteristics of aging is the loss of reproductive ability in mid-adulthood,” said Coleen Murphy, a professor at the Princeton University. “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,” Murphy added. The team used a microscopic worm, Caenorhabditis elegans (C.elegans), as they share many of the genes as humans, including longevity genes. They found that a group of proteins called Cathepsin B proteases “downregulate”, or lead to lower-quality oocytes (unfertilized eggs), as one ages. When the team administered the Cathepsin B inhibitor halfway through the worms’ reproductive period, they found that even a late administration of the drug could extend the worms’ egg quality. Another experiment that knocked out the cathepsin B genes entirely succeeded in extending worms’ fertility by about 10 percent. If applied to humans, Nicole Templeman from the varsity said, “It could be a three to six-year extension of your reproductive period”. The reproductive decline is a hallmark of aging, but despite its prevalence, interventions to slow the loss of reproductive capacity are lacking, researchers said. However, the cathepsin B inhibitor is nowhere near ready for testing in humans, Murphy said, yet it could one day do something mid-reproduction to improve the rest of reproduction. The study was published in the journal Current Biology.