Our fertility window could be extended by making ovaries softer

A drug that softens the ovaries helped mice and rats conceive more easily at an older age, and produce more pups

A drug that softens the ovaries helped mice and rats conceive more easily at an older age, and produce more pups

Light micrograph of a section through follicles, which house immature eggs, in an ovary. The immature eggs (orange) are surrounded by fluid-filled cavities (light pink) and granulosa cells (dark pink), which provide them with nutrients and hormones

Our fertility window could be extended by making the ovaries less stiff. A drug that softens the organ more than doubled the conception rate of older rats with declining fertility and increased their litter size fivefold. It needs to be tested on women, but the results have raised hopes that the intervention could help them conceive at an older age.

Women’s fertility tends to start declining in their mid-thirties. However, in countries like England and Wales, many are choosing to have children later in life . The number and quality of a woman’s immature eggs, one of which matures and is released during ovulation, decline with age. There is also evidence that ovaries become stiffer over time, which may further affect egg development and quality.

To understand what’s driving this, Shixuan Wang at Huazhong University of Science and Technology in Wuhan, China, and his colleagues measured the protein levels of the ovaries of women aged 18 to 28, 35 to 42, and 47 to 52. All of the women had a history of gynaecological cancer; however, their ovaries were unaffected when removed.

The researchers found that a protein called interleukin-11 increased in the ovaries with age. This activates cells in connective tissue called fibroblasts, which make collagen – a driver of ovarian stiffness .

Next, the team genetically modified a group of mice to be unable to respond to interleukin-11. Not only did this reduce ovarian stiffness – measured via microscopy – as the mice aged, but the animals also ovulated more than an unmodified control group.

Your science-backed guide to the easy habits that will help you sleep well, stress less, eat smarter and age better.