Research Gaps in Menstrual Disorders Beyond Endometriosis

Over the last decade, funders have paid more attention to women's health, but most menstrual disorders remain barely better understood than before. Endometriosis has absorbed the spotlight, while comparably common conditions, including dysmenorrhea, adenomyosis, uterine fibroids, heavy menstrual bleeding, and PMDD, receive scant study despite causing a similar burden. The imbalance follows long-running NIH choices: breast cancer, pregnancy-linked health, and the menopause transition have drawn a disproportionate share, while the National Academies' 2025 report A New Vision for Women's Health Research: Transformative Change at the National Institutes of Health concluded that support is still sparse and uneven for fibroids, pelvic floor problems, and other conditions specific to females. The overall budget has not been contracting. Seen broadly, the problem may resemble one underfunded area, but it is a pileup of distinct gaps: every disorder here has been overlooked in its own way, with harms compounded by the cultural tendency to normalize menstrual suffering rather than investigate it.

How Normalization Keeps Patients Out of Clinical Settings and Research Pipelines

Cultural normalization does quiet damage to research pipelines before any grant committee ever gets involved. When menstrual pain or heavy bleeding gets treated as an ordinary part of life rather than a medical symptom, people stop seeking care for it, doctors stop diagnosing it, and clinical research never gains access to the population it depends on. Dysmenorrhea shows this most clearly: Roos et al., writing in JMIR in 2025, found that among women reporting symptoms consistent with the condition, only 4.6% said they had ever been diagnosed with it, regardless of how severe their pain was. The same researchers identified the specific mental habits behind that gap: women tend to view their discomfort as normal, read it as a mood issue rather than a physical one, and stay quiet out of embarrassment or broader stigma around menstruation. Adenomyosis follows a related path. Many women with the condition describe feeling dismissed by the clinicians they do manage to see, a pattern serious enough that researchers studying the condition have concluded that closing the gap will require nothing short of a cultural shift in how menstrual symptoms are received in the exam room.

For research, the result is plain and direct. When most people with a condition never reach clinical care, trials cannot recruit them, registries do not record them, and the electronic health records that increasingly shape researchers’ next questions leave them out. When clinicians never see a condition, the machinery behind today’s medical research misses it as well; that absence becomes grounds for more underinvestment, with funders treating the recorded need as scant, spending accordingly, and leaving the evidence too thin for demand to appear large. The cycle tightens without notice, case by case, as each person takes her pain to be ordinary.

Where the research gaps are sharpest: a condition-by-condition account

Not every condition takes the same hit from the research deficit. Neglect looks different, and is documented separately, in adenomyosis, dysmenorrhea and HMB, plus PMDD and fibroids, so anyone weighing which conditions deserve fresh funding first has to tell them apart.

Dysmenorrhea ranks first in terms of sheer prevalence. A 2025 Tandfonline public health review ranks dysmenorrhea among the most prevalent menstrual conditions ever documented, even though scientists still do not fully understand the biological processes driving its pain. This basic-science gap carries practical weight. Doctors struggle to foresee which patients will face intense menstrual pain or to catch risk factors soon enough, especially during the early years of life, when neural circuits adapt most readily and early help would likely pay off the most over time, a blind spot that counts since dysmenorrhea raises the odds of chronic pelvic pain in adulthood. Care itself still fails a sizable group: about one in five women who have dysmenorrhea get no relief from NSAIDs, the usual first-line therapy. The limits are in existing treatment knowledge itself, not just in access to it.

Adenomyosis opens up an even bigger gap in treatment. The condition drives heavy bleeding, painful periods, ongoing [pelvic pain, and impaired fertility, yet nothing is licensed to treat it, and a 2025 eBioMedicine paper found adenomyosis studies trailing work on both leiomyoma of the uterus and endometriosis.] A 2025 synthesis of how patients actually experience the condition and the path they take to diagnosis surfaced impacts beyond physical symptoms, affecting relationships, work, and personal money, burdens that land on those affected but that today's research frameworks are not designed to measure.

With one in three women experiencing heavy menstrual bleeding (HMB), the scarcity of therapeutic choices is remarkable. A University of Pennsylvania physician, Kathleen O'Neill, MD, has characterized available treatments as severely constrained. Two distinct shortcomings underlie this constraint. Because practitioners frequently cannot pinpoint why HMB occurs and no uniform metric exists for assessing it, funded research rarely yields findings that align meaningfully with other trials.

The gap in PMDD studies comes into focus through comparison. PMDD affects far more people than postnatal depression, yet NIH support remains low for its scale, a mismatch documented in a 2025 analysis in Frontiers in Psychiatry. Studies of psychiatric symptoms across the menstrual cycle are still few, although Susser, Hantsoo, and Osborne call the area a fast-growing one in Frontiers in Psychiatry and highlight sharper risk-factor mapping and care advances rooted in biology. The larger problem reaches beyond PMDD.

Both conditions wrap up the overview here, though each receives more detailed attention in other sections of this coverage. By comparing what the NIH allocates annually to PCOS against sums for similar disorders, a Fertility & Sterility review showed that spending remains disproportionately small given the syndrome's prevalence, its financial toll on individuals and medical infrastructure, and its impact on well-being. With as many as 80% of women in their childbearing years affected by fibroids, the sheer scale alone demands substantial scientific funding, while racial disparities within this issue are pronounced enough to merit separate, in-depth analysis.

Racial Disparities in Fibroid Research

Fibroids reveal how gaps in menstrual research burden some groups far more than others. Black women are diagnosed with fibroids far more often and endure harsher disease, yet they must overcome the hardest obstacles to prompt diagnosis, fair care, and a place in the research meant to serve them. Dixon et al. writing in a 2026 Journal of Racial & Ethnic Health Disparities paper, link Black patients’ delays in diagnosis and care to limited public understanding, stigma around menstruation, and well-founded mistrust of healthcare rooted in generations of experience.

That disadvantage manifests in how patients are treated. In their Journal of Minimally Invasive Gynecology analysis, Louie et al. documented that Black patients were assigned a greater likelihood of undergoing the most aggressive fibroid intervention than White patients, while socioeconomically disadvantaged patients more often received care at the invasive extreme of available options. If researchers had prioritized fibroids decades ago and monitored racial outcomes from the beginning, they might have identified and fixed that disparity before it became standard clinical care.

Rather than fixing the inequity, the trial pipeline deepens it. Black women are enrolled in fibroid-treatment trials at low rates, despite bearing far more of the condition’s U.S. burden. Fibroid care guidance still rests on studies that largely excluded the very patients those decisions should prioritize. The representation gap is wider still. Across menstrual-health science, cisgender women have been the near-exclusive focus, leaving little evidence on the experiences or needs of transmasculine and non-binary menstruators, with studies of this group still scarce.

The Measurement and Siloing Problems

Faced with this, one might reasonably conclude that growing NIH budgets will sort it out over time, that increased funding for research into women's health will gradually make its way to conditions like PMDD, fibroids, HMB, and adenomyosis. But that expectation fails, since two structural problems, namely tools that measure inconsistently and the isolation of menstrual studies from mental health studies, result in even generously funded studies frequently generating evidence that is neither actionable nor comparable.

The first hurdle is getting measurement right. Research on heavy menstrual bleeding (HMB) alongside dysmenorrhea continues to use mismatched measures for symptom burden and life-quality impact, without a common yardstick for defining affected populations’ needs. Because studies measure outcomes differently, their findings cannot be merged across projects. As a result, research remains too scattered to generate the pooled evidence needed to advance treatment guidelines. The gap is even wider for dysmenorrhea and adenomyosis, since there is no registry for either condition and no broad data system to support large cohorts, natural-history work, or long-term treatment follow-up.

The divide separating menstrual health research from mental health research runs parallel to inconsistent measurement rather than sitting below it. Menstrual health studies and mental health studies have long moved along separate paths, with each field sidelining the other instead of viewing them as a unified biopsychosocial whole, a shortcoming the Frontiers in Psychiatry analysis from 2025 argues demands a more holistic approach. Funding invested in either field alone will continue to overlook how they interact.

NIH budget history turns the broader funding issue into a concrete example. Over the past decade, NIH has awarded more in research grants overall, but the portion reserved for women's health research has stayed flat, showing that added systemwide funding will not by itself move toward neglected conditions unless a structural force pushes it there. The National Academies' 2025 report carried that reasoning forward by urging Congress to turn NIH's Office for Research about Women's Health into a full Institute, reshaping the organization instead of merely adding a budget line, because agency design helps determine where money goes.

Recent Investments and What They Leave Unresolved

From 2024, three projects have begun tackling parts of this, but they don't fix deeper structural gaps like inconsistent measurement, the lack of registries for diseases, or Global South data being nearly absent. The field has also absorbed one big infrastructure setback working against that progress.

Through its Missed Vital Sign program, Wellcome Leap is supporting HMB research on measurement, underlying biology, treatment development, and education for patients and clinicians about normal versus abnormal menstrual bleeding. Backed by multi-million-dollar support, Kathleen O'Neill and her University of Pennsylvania team, led by her as MD, are testing a non-hormonal, mRNA-based approach to HMB, showing what focused funding can achieve when it zeroes in on the precise biology still not understood instead of a sweeping, unfocused brief.

Another line of work fills a separate gap in the evidence base: in December 2025, Gates Foundation Grand Challenges funding went to Sara Khalid's Planetary Health Informatics team at the University of Oxford, supporting a study of the epidemiology and burden of heavy menstrual bleeding across low-resource settings, aimed squarely at how little solid Global South data exists on the condition.

A third change is structural instead of programmatic. The NIH's Office of Research on Women's Health requested that the National Academies evaluate the agency's work in this field, pinpoint major knowledge gaps, and propose a way forward, yielding the report referenced throughout this piece. Whether pursued alone or jointly, these initiatives fail to establish uniform metrics for studying dysmenorrhea alongside HMB, leave both conditions without the patient registries they require, and do nothing to improve representation among menstruating transgender, non-binary, and Black individuals.