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For decades, the standard line on ovaries after menopause has been blunt: once the eggs run out, the job is done, and the ovaries shrink into quiet, dormant little organs that do not do much at all. New research from Northwestern University suggests that picture is wrong. When the reproductive years end, the ovary may pick up a second career as something closer to an immune organ.
In a study published in Molecular Human Reproduction in 2026, Francesca Duncan’s lab at Northwestern’s Feinberg School of Medicine found that the ovaries of old mice fill up with immune cells and switch on genes and proteins tied to immune activity.
Some of those signals look as though they could be released into the body more widely, not just inside the ovary. Their conclusion is striking: the post-reproductive ovary appears to shift from a reproductive organ to an immune-like one.1
This is early work, mostly in mice, with some supporting human data. We do not yet know whether this second job is helpful, harmful, or a bit of both. But it is a genuine shift in how scientists think about the ageing ovary, and it matters for anyone who has been told their ovaries are simply switched off after menopause.
Do ovaries do anything after menopause?
Yes. The idea that ovaries become useless after menopause has never been quite true, and this research pushes back on it harder than ever.
Even after periods stop, the ovaries keep making small amounts of hormones, particularly androgens (such as testosterone), which the body can convert into a form of oestrogen in fat and other tissues. That low-level hormone production carries on for years, which is one reason the decision to remove healthy ovaries during other surgery is taken seriously rather than waved through.
What is new here is the suggestion that the ovary does not just keep ticking over hormonally. It may take on a recognisably immune role, with immune cells moving in and immune-related genes ramping up as reproductive life winds down.
What the Northwestern study actually found
The team compared ovaries from young, reproductively old, and post-reproductive mice, pairing tissue analysis with a read-out of which genes were switched on.1 A few things stood out.
As the ovaries aged and ran out of follicles (the structures that hold eggs), they became increasingly populated by immune cells. The genetic activity in those older ovaries leaned heavily towards immune and inflammatory programs, rather than the reproductive ones that dominate earlier in life.
Some of the immune signals the ovaries produced looked capable of acting beyond the ovary itself, raising the possibility that the post-reproductive ovary contributes to the body’s wider immune and inflammatory tone. The researchers also point to human data pointing in a similar direction, though the human side is still thin.
The original focus of this line of work was senescent cells, the worn-out cells that stop dividing but linger and leak inflammatory signals as we age. The ovary is one of the first organs in the body to show its age, so it is a natural place to study that process. The immune-organ finding grew out of that work rather than replacing it.
Inflammation, inflammaging and why this is double-edged
This is the part to hold loosely, because the science has not settled it. Immune activity is not automatically good news. As we age, the body tends to sit in a state of low-grade, chronic inflammation, sometimes called inflammaging, and senescent cells help drive it through the inflammatory cocktail they secrete.
So an ovary that becomes more immune-active in later life could be doing something protective, or it could be adding to that background inflammation, or its role could change depending on the person and the tissue. The honest answer right now is that we do not know which, and the researchers are careful to say so.
What this does do is reframe menopause itself. Rather than an organ simply switching off, this looks like an active biological transition, with the ovary changing what it does rather than just stopping.
What this means for your vagina and vulva
The ovaries sit upstream of a lot of vaginal and vulvar health, mostly through the hormones they make. As ovarian oestrogen falls across perimenopause and beyond, vulvovaginal tissue gets thinner, drier and less elastic, the vaginal pH drifts upward, and the protective vaginal bacteria (the lactobacilli that keep the environment acidic and stable) lose their footing.
That cluster of changes is now grouped under genitourinary syndrome of menopause (GSM), which covers dryness, irritation, painful sex and recurrent urinary symptoms.
If the ovary is also an immune and inflammatory player in later life, that adds another thread to the picture. Inflammation does not stay tidily in one organ, and the vaginal and vulvar tissues are immune-rich and sensitive to the body’s overall inflammatory tone. It is too early to draw a straight line from this mouse study to your symptoms, but it strengthens the case that menopausal vaginal changes are about more than oestrogen alone.
In our clinic, we see a lot of postmenopausal vaginal complaints that have been written off as ‘just dryness’ or ‘just ageing’, when the underlying drivers are a mix of low oestrogen, a shifted microbiome and a more inflammatory internal environment. We tend to work across all of those at once rather than treating the dryness in isolation, because the tissue rarely settles when only one piece is addressed.
Why women’s reproductive organs stay understudied
One reason a finding like this lands as a surprise is that the ovary has been comparatively neglected. It ages faster than almost any other organ, yet it has had a fraction of the research attention given to the heart or brain, and the post-reproductive ovary in particular has been treated as a spent organ not worth a close look.
That gap is exactly why work like this is worth flagging. The more we treat the ovary as an active organ with a changing job description, the better the odds of understanding what menopause does to the rest of the body, including the bits we care about most here.
Frequently asked questions
Are postmenopausal ovaries useless?
No. They keep producing small amounts of hormones for years after periods stop, and this new research suggests they may also take on an immune-related role. ‘Dormant’ is not an accurate description.
Does this study apply to humans?
Not directly yet. The main findings are from mice, with some supporting human data. A similar shift in humans is plausible but not proven, and the health consequences are still unknown.
Is the ovary’s immune activity good or bad?
Unclear. Immune activity can be protective, but in ageing tissue it can also feed chronic, low-grade inflammation. This study does not settle which way it goes.
Should this change whether I keep my ovaries?
It does not give a simple rule either way, and it is not a reason to make a decision on your own. Whether to keep or remove ovaries during surgery is an individual call to make with your specialist, weighing your age, history and risks. You can read more about the ovaries in our piece on premature ovarian insufficiency.
How does this relate to my vaginal symptoms?
Indirectly. The ovaries shape vaginal health largely through hormones, and falling oestrogen drives most menopausal vaginal changes. If the ovary also influences body-wide inflammation, that may be one more piece of the puzzle, but the link to symptoms is not yet established.
What to do next
This is a research story rather than a to-do list, so there is nothing to buy and nothing to change off the back of it. If menopausal vaginal or vulvar symptoms are bothering you, those are very treatable and worth addressing properly rather than putting up with.
A good first step is understanding what is actually going on with your tissue and microbiome. If your symptoms point to a possible microbiome shift, a comprehensive vaginal microbiome test gives a much clearer picture than guesswork.
It can also help to read up on what a protective vaginal microbiome looks like and how oestrogen ties into the wider hormonal picture via the estrobolome. For tailored help, you can book an appointment with our team.
This is general information, not a substitute for personalised medical advice.
- Converse A, Dipali SS, Schowe IP, Kelly EB, Jambunathan SS, Ocañas SR, Stout MB, Pritchard MT, Duncan FE. The post-reproductive ovary shifts from a reproductive to an immune-like organ. Mol Hum Reprod. 2026;32(2):gaag038.
