After menopause, ovaries have long been presumed “ functionally useless ,” shutting down with the conclusion of fertility. As harsh as this sounds, it has been an assumption for generations, given the ovaries’ primary role as a reproductive organ. Only in the past decade have scientists really begun to investigate ovaries outside the lens of reproductive viability, and sure enough, the term “useless” was far from correct.

A 2026 study from Northwestern University found evidence suggesting a transition into an immune role, which could be operating far beyond the ovarian tissues to impact whole-body aging and immunity. By examining the ovaries of mice at different stages during and after the reproductive cycle, the team discovered differences in gene expression across the lifespan. Although mice don’t directly go through menopause, their ovaries stop producing eggs in a similar way to humans, making them a useful model. The results imply a potential for ovaries to produce secreted immune factors and impact inter-organ communication during aging.

To explore ovarian identity and function throughout the lifecycle, the study evaluated reproductively young (two-month-old), reproductively old (18-month-old), and post-reproductive (24-month-old) mice. In each mouse, one ovary was designated for histological analysis, which examines tissue, and the other ovary was used for bulk RNA sequencing, which measures gene expression. Follicles were counted to determine the reproductive period timeline. Analysis of gene expression showed that while follicle signatures and cells were lost from the post-reproductive ovary, there was an acquisition of immune and inflammatory phenotypes.

The data showed that following cessation of reproductive function, the ovary is far from inert. It transitions from a reproductive organ to one with a more immune-focused genetic signature, which could have significant implications for immune health and, particularly, the skewed prevalence of autoimmune conditions in women. With age, women often exhibit greater hyperactivation of both innate and inflammatory pathways than men, which correlates with increased prevalence of autoimmunity. This raises the question: Could inflammatory signaling from the post-reproductive ovary contribute shifts in systemic immunity?

Up to 50 million Americans suffer from autoimmune diseases, and women are affected disproportionately. There are at least two women for every one man suffering from an autoimmune disease, and prevalence is even higher in female populations over age 40 . This is just one implication of researching ovarian immune function. Studying ovarian immunity could also help scientists understand and address age-related ovarian decline, and may eventually lead to innovative therapeutics for protective interventions.

Ovaries have much more to offer than their reproductive capabilities. While critical, fertility is one of many fields in ovarian research, not the sole focus. This mouse study is an important first step in the journey to truly understand post-reproductive ovaries in humans. Women need answers about menopause, aging, and immunity, and prioritizing research on ovarian immune function and women’s health as a whole would accelerate science toward this goal.