Why the Period Gap in Medical Research Is So Big, Explained

What you will learn about the period gap in medical research in this blog:

• Women were excluded from medical research for decades, so many treatments and diagnostic standards were built around male bodies. 
• Conditions like endometriosis and PMDD are still underdiagnosed and under-researched despite affecting millions of women. 
• Menstrual and reproductive health research receives far less funding than many male-focused health conditions. 
• With limited research available, period pain is often dismissed, minimised, or treated as emotional rather than physical. 
• Delayed diagnoses for conditions like endometriosis can lead to years of untreated pain, fertility issues, and emotional exhaustion. 
• Tracking symptoms clearly and asking directly for investigations or referrals can help women advocate for better medical care. 

Here are some facts that explain the period gap in medical research: 

Endometriosis, a condition that affects roughly 1 in 10 women, takes an average of 6.6 years to diagnose worldwide, and in the UK some women have waited up to 27 years.

PMDD, a hormonal condition severe enough to upend lives, was only added to the DSM (the medical bible used to diagnose psychiatric conditions in the US in 2013. 

On the flipside, as of 2015 there were five times more studies on erectile dysfunction, which affects about 18% of men, than on PMS, which affects around 90% of women. 

None of that is an accident. It is the gender gap in medical research, and it follows you around every time you’re in your doctor’s clinic.

This blog post is about why that gap exists, what the science actually says, and how it shapes the moment you sit on that paper-covered table in the clinic and try to explain that your cramps are not normal. Because here is the uncomfortable part, a lot of doctors have simply never read a paper about your pain. What more uncomfortable? There often isn’t one to read.

How Women Got Written Out Of The Research In The First Place

For a long stretch of modern medicine, the default human body in a study was male. In 1977, the US FDA actually issued guidance that excluded women “of childbearing potential” from early-phase drug trials. The rule was framed as protection, partly a reaction to the thalidomide tragedy, when a morning-sickness drug caused severe birth defects in thousands of babies and made regulators wary of exposing any woman who might conceivably be pregnant. But slowly, it started including all single women, women on contraception, and women whose partners had vasectomies too. The female body was treated as too variable – because of hormone fluctuations – and too risky to study, so it mostly wasn’t.

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That ban wasn’t reversed until the NIH Revitalization Act of 1993 made including women in federally funded research the law. Think about how recent that is. If you are reading this and you are over thirty, the requirement to even study people like you is younger than you are. Decades of foundational research, the stuff that became textbooks and dosing guidelines and the instincts doctors are trained on, was built on bodies that don’t have cycles.

The fallout was real and measurable. Because so much early work skipped women, sex-based differences in how drugs are absorbed and metabolised went unstudied, which is how a sleep drug ended up being dosed too high for women for years before anyone caught it. These male-centric medical studies didn’t just leave women out of the data. They set the baseline for what “normal” looks like, and women have been (incorrectly) measured against it ever since. It is also why the basic biology of your cycle, the cramps, the flow, the hormone swings, stayed under-mapped for so long. For most of modern medicine, nobody was funded to look.

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How Funding Decides What Gets Known: Widening The Gender Gap In Medical Research Further

Research needs funding, and funding reveals priorities. When you line up the numbers, the menstrual health medical research picture gets hard to defend. A study in the Journal of Women’s Health analysed NIH funding against actual disease burden and found that in nearly three-quarters of cases where a disease mostly affects one sex, the funding pattern favours men. Conditions that hit women hardest were consistently funded below the level their burden would justify.

A few comparisons to confirm this are:

• Premenstrual conditions affect up to 90% of women, yet they receive a fraction of the funding of erectile dysfunction, which affects under 20% of men.
• Between 2019 and 2023, startups tackling erectile dysfunction and similar men’s health concerns raised $1.24 billion, while endometriosis startups raised about $44 million.
• One analysis found endometriosis receives less research funding than male-pattern baldness, a condition that causes no pain and no infertility.

This is the engine of the period pain research gap. When something isn’t funded, it isn’t studied. When it isn’t studied, there are no papers, no clinical guidelines, and no specialist consensus. The silence compounds. It is a big part of why women’s health is under researched, and the effect snowballs across generations of doctors who were trained on whatever evidence happened to exist.

To Truly Understand the Problem, Look No Further Than Period Pain

Dysmenorrhea affects somewhere between 45 and 95% of menstruating people, and severe cases can knock out work, school, and sleep. Each month the lining of your uterus releases prostaglandins (more on that here), chemicals that make the uterine muscle squeeze hard to shed that lining. That much is settled. Almost everything more specific than that gets blurry fast, which is remarkable for something that affects as many people as it does. 

You’ve probably seen the line that period pain can be “almost as bad as a heart attack.” It traces back to one reproductive health professor repeating what his patients told him, not to a controlled study, because no research has ever actually measured period pain against heart attack pain. Researchers are also openly unsure why some people are floored by cramps every month while others barely register them, calling the reasons still unclear. That uncertainty is the period pain research gap in a single sentence: the pain is real, it is nearly universal, and the science to explain it barely exists. This blind spot has a name, the gender gap in medical research, and period pain sits very close to its centre.

None of this means severe cramps are just a rough few days to wait out. Bad period pain has been linked to chronic pain conditions later in life, yet a landmark 2011 commentary in the journal Pain was literally titled Don’t dismiss dysmenorrhea, and it described how period pain had been virtually ignored by the pain research community despite how many people it floors every single month. 

Why Your Period Cramps Get Waved Off

The research gap doesn’t stay in the lab. It walks into the appointment with you. Here is how period pain dismissed by doctors actually happens, point by point, and why it is rarely about one bad doctor.

1. The evidence base is thin, so instincts fill the gap: When there are few papers on menstrual pain, a clinician leans on training and gut feeling instead of data, and gut feeling carries old assumptions about women exaggerating.
2. Women’s pain is rated lower even with identical symptoms: In a study of over 21,000 emergency records, women were less likely to receive pain medication than men reporting the same pain level, and this held true whether the treating doctor was a man or a woman. There is an intrinsic belief that women are more tolerant, belief being the keyword here.
3. It gets documented less: In that same research, nurses were 10% less likely to even record a pain score for female patients, which means the suffering doesn’t fully make it into the chart that drives treatment.
4. “Hysteria” never really left: Reviews of pain care show women are still more likely to have symptoms read as emotional or psychosomatic rather than physical, an echo of centuries old assumptions about women’s bodies.
5. Periods fall between specialties: Menstrual symptoms can touch gynaecology, endocrinology, and pain medicine at once, so the issue slips through the cracks and no single field fully owns it.

Put those together and you get the honest answer to why doctors ignore period pain: not malice, usually, but a system where the data is missing, the bias is ambient, and the normalisation of women’s pain is so old it feels like common sense. The hormonal health research gaps mean even a well-meaning doctor is often improvising.

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What The Period Gap In Medical Research Actually Costs You

The endometriosis diagnosis delay is the textbook example. Because there is still no simple, validated non-invasive test, and diagnosis often depends on a doctor first taking the pain seriously, then referring onward, then waiting for a laparoscopy. Each handoff is a place to be doubted. A UK parliamentary group found 58% of endometriosis patients had visited a GP more than ten times before getting a formal diagnosis.

Behind every statistic is a person who knew something was wrong and kept being told otherwise. When someone says their endometriosis took years to diagnose, what they usually mean is that they spent those years being told the pain was normal, stress-related, or in their head, while the disease kept progressing. 

The same silence shows up in something as basic as how much you bleed. Heavy menstrual bleeding affects roughly 1 in 5 women, yet plenty of people never flag it, partly because if your mother and sisters bled the same way, soaking a pad an hour just registers as “your normal”. Some of those heavy periods are the first visible sign of a bleeding disorder like von Willebrand disease, where the diagnostic delay for women can stretch past 14 years. It is hard to ask for help with a problem no one ever told you was a problem.

And it isn’t only endometriosis. The same dynamic shows up across PCOS, PMDD, adenomyosis, and chronic pelvic pain. Less research means fewer diagnostic tools, which means longer delays, which means more people quietly deciding the problem must be them. That feedback loop is the gender gap in medical research operating on you personally, one dismissed appointment at a time.

How To Be Heard At Your Next Appointment

You can’t single-handedly fix the gender gap in medical research, but you can change the odds in your specific appointment. 

1. Track before you go, in numbers: For two to three cycles, log pain on a 0–10 scale, days missed from work or school, products used per hour on heavy days, and any symptoms that travel with your period like nausea, fainting, or diarrhoea. Concrete data is harder to wave away than “it hurts a lot.”
2. Lead with function, not just feeling: Say what the pain stops you from doing. “I miss two days of work every cycle” lands differently than “my cramps are bad,” because it signals impact a clinician has to act on.
3. Use the words that trigger action: Phrases like “I’d like to rule out endometriosis,” and “what would it take for this to get further investigation?” move you from comfort-and-reassure toward actual assessment.
4. Ask for it in writing: If you’re told the pain is normal, calmly ask them to note in your records that you raised it and the conclusion was no further action. People rarely have to write that down, and the request alone often reopens the conversation.
5. Bring a second set of ears: Research on period pain dismissed by doctors shows a witness in the room changes how seriously symptoms are treated. A partner or friend who can say “I’ve seen her collapse from this” adds weight you shouldn’t need but can use.
6. If you’re stonewalled, ask for a referral by name: Request a gynaecologist or a specialist pelvic-pain clinic directly. You are allowed to decline “let’s wait and see” when you’ve already waited.

Every one of those moves is really you supplying the data and reproductive health awareness that the research pipeline failed to generate. You’re doing unpaid work to cover for a system-wide blind spot, which isn’t fair, but it works, and it’s worth knowing how.

The Gap Is Closing, Slowly, And You’re Part Of Why

There is genuinely good news. Period pain is finally drawing serious scientific interest after decades of neglect. Funding for women’s health is being scrutinised more openly than ever. Plus, a generation of patients is refusing to accept “that’s just being a woman” as a diagnosis. 

The gender gap in medical research took fifty years of exclusion to build, so it won’t vanish overnight, but the direction has changed.

Until the science fully catches up, the most radical thing you can do is keep believing your own body. Your cramps and your missed days are data. Your insistence in a doctor’s office, however inconvenient, is part of how the evidence base finally gets written. The next person who walks in with the same pain will be heard a little faster because you refused to be quiet.

Disclaimer: 

The content of this article is provided for general informational and educational purposes only and is not intended to constitute medical advice, diagnosis, or treatment. The information shared is of a general nature and may not be appropriate for all individuals or specific circumstances. Readers should not disregard, delay, or substitute professional medical advice based on the information contained herein.

If you experience any symptoms, notice anything unusual, or have concerns relating to your health or overall wellbeing, you should consult a qualified healthcare professional. While every effort is made to ensure the information shared is accurate and up-to-date, Nua makes no representations or warranties, express or implied, regarding the accuracy, completeness, or suitability of the information provided and disclaims all liability arising from reliance on this content to the fullest extent permitted by law.