Why Ovaries May Still Matter After Menopause: New Research Raises Important Questions

Residual hormone production may become less important over time, but that does not mean the ovaries stop playing a role in women’s health, says Walter Rocca, a professor of epidemiology and neurology at the Mayo Clinic.

“Until proven otherwise, we remain convinced that it is not a good idea to have your ovaries removed, even after menopause,” Rocca said. He cautioned that this does not apply in the same way to women at high risk for ovarian cancer, for whom the potential benefits and risks of ovary removal may differ.

How Long Do Ovaries Matter After Menopause?

How long the ovaries remain important after menopause is still an open question, says Stéphanie Fabion, medical director of the Menopause Society. Researchers also do not yet know how much the answer varies from woman to woman.

“We just have a huge gap,” Fabion said.

Duncan’s research suggests that the role of postmenopausal ovaries may change over time. After analyzing human ovaries, researchers found protein patterns suggesting that older ovaries become a more inflammatory environment.

To better understand what might cause these changes, the researchers examined mouse ovaries. Their study was published in June in the journal Molecular Human Reproduction. The findings suggest that ovaries may eventually take on an entirely different biological identity after menopause.

Why Aging Ovaries May Become More Inflammatory

The researchers compared mouse ovaries at 2, 18, and 24 months of age. Over time, genes associated with inflammation and immune activation became much more active. The number of immune cells in the ovaries also increased.

Research in mice does not necessarily apply to humans, but it may help explain the molecular changes Duncan observed in human ovaries.

“We think that many of these changes may make the ovaries more susceptible to age-related diseases such as ovarian cancer,” said Birgit Schilling, an aging researcher at the Buck Institute on Aging. Schilling collaborated with Duncan on research involving human ovaries, which was published as a preprint.

After menopause, the risk of several conditions—including stroke, heart disease, and osteoporosis—increases or may be exacerbated.

Could Aging Ovaries Affect the Rest of the Body?

Other organs also undergo immune remodeling as they age, but the ovaries appear to age much faster than most other organs. Duncan’s research raises the question of whether, at some point, the risks of keeping the ovaries could outweigh the benefits.

As aging ovaries become more inflamed, Duncan wonders whether they might begin sending inflammatory signals to other parts of the body.

Can Ovaries Continue Producing Hormones After Menopause?

David Pepin is exploring another possibility: that the ovaries may reorganize to maintain hormone production as the follicles that house developing eggs disappear.

Pepin, a reproductive biologist at Massachusetts General Hospital and Harvard Medical School, found that several years after cats received an experimental contraceptive gene therapy that prevented follicle maturation, they continued to produce normal levels of estrogen, testosterone, and inhibin.

Follicles drive much of the ovary’s hormone production during the reproductive cycle, so hormone levels would be expected to fall without them. In preliminary work that he announced publicly, Pepin’s team found that when the ovary was eventually removed, other cells within the ovary—known as the stroma—appeared to take over hormone production.

A pilot study in mice suggests similar effects. Pepin believes the findings may point to a natural mechanism that helps maintain hormone production even as ovarian follicles decline. The possibility that the stroma contributes to hormone production after menopause in humans has long been hypothesized.

Much More Remains Unknown About Postmenopausal Ovaries

Estrogen is not the only hormone involved in menopause. “Little is known about how other ovarian hormones that are altered during menopause contribute to health,” the researchers said.

The findings reinforce the idea that the ovaries are not simply inactive after menopause. As one researcher put it: “It’s not a dead organ.”