Recent studies indicate that by softening ovarian tissue, it may be possible to enhance fertility rates. A novel drug aimed at reducing organ hardness more than doubled conception rates and increased litter sizes five-fold in older, subfertile rats. While human trials are necessary, these findings spark optimism that similar interventions could aid older women in conception.

Female fertility significantly declines in the mid-30s. However, in regions like England and Wales, many delay childbirth, often until later in life. The quantity and quality of a woman’s immature eggs decrease with age, supported by evidence that ovarian stiffness increases over time, affecting egg development and quality negatively.

In a study led by Wang Shixuan, researchers at Huazhong University of Science and Technology analyzed protein levels in the ovaries of women aged 18 to 28, 35 to 42, and 47 to 52, all with a history of gynecological cancer that did not impact the ovaries after removal.

The findings revealed an increase in a protein called interleukin-11 in aging ovaries. This protein activates fibroblasts, connective tissue cells that produce collagen, contributing to ovarian stiffness. Learn more about the causes of ovarian stiffness.

The research team also genetically modified mice to resist interleukin-11, resulting in reduced ovarian stiffness and increased ovulation compared to unmodified mice.

Subsequently, the researchers tested an experimental drug to inhibit interleukin-11 production by silencing its gene, administering it to 36-week-old mice, analogous to humans in their late 30s or early 40s, twice weekly for a month.

Results demonstrated a 36% decrease in ovarian firmness compared to untreated controls. Conception rates increased from 25% to 50%, and average litter sizes grew from three to five calves. Similarly, in aged rats, conception rates improved from 20% to 50%, with litter sizes increasing fivefold from one to five.

Francesca Duncan from Northwestern University in Illinois remarks that this intervention may yield comparable results in premenopausal women, noting that interleukin-11 levels also rise with age in human ovaries. However, she cautions that findings are based on women with a cancer history, leaving questions about its effect on individuals without such health concerns.

Additional studies are needed, as indicated by Barbara Vanderheiden of the University of Ottawa, who suggests potential broader benefits for women’s health. “Preserving fertility and extending ovarian function could mitigate menopause effects like osteoporosis and heightened heart disease risks,” she notes.

The goal is to deliver the drug directly to the ovaries ahead of human trials. So far, no adverse effects have been observed in mice and rats. Yet, Duncan warns of risks since interleukin-11 is present in various human tissues. “Considering the pivotal role of ovarian egg cells in future generations, drug safety protocols targeting the ovaries must be exceptionally stringent,” she states.

Questions remain about the duration required for the drug to enhance reproductive outcomes. “While reducing ovarian stiffness could be feasible,” Vanderheiden states, “short-term treatments show limited data on their long-term positive or negative impacts.”