Jenneh Rishe, a registered nurse, is not the type to let a health mystery go unsolved.

At age 30 and living in Los Angeles, she was determined to suss out the cause of the abdominal pain that sent her to the ER seven times in two years, as well as other symptoms like shortness of breath. She'd seen specialists including OB/GYNs pulmonologists and cardiologists. But the tests always came back normal.

"I thought maybe I'm dying or I have some kind of rare disease. But then I go online and find millions of women are going through exactly what I'm going through," Rishe explained.

She shared the story in the first few minutes of Below the Belt: The Last Health Taboo, a new documentary that follows four people on a years-long search for effective treatment for endometriosis.

This chronic inflammatory disease, which often causes severe pain during menstruation, is often poorly understood. People with endometriosis have tissue similar to that found in the uterine lining growing outside of the uterus, sometimes on the ovaries, fallopian tubes, bowel or other organs.

In addition to sometimes debilitating menstrual pain, it can cause heavy bleeding and infertility. In one international study, women lost an average of 10.8 hours per week of work due to endometriosis symptoms.

"Even though endometriosis feels like a strange, foreign word and unfriendly to most people who've never heard of it, the fact of the matter is that it affects everyone," said the film's director Shannon Cohn, in an interview with NPR. "Either you have it or you love someone who has it."

The disease affects an estimated 1 in 10 women of reproductive age according to the American College of Obstetricians and Gynecologists. Cohn says ignorance around the disease – both in the public and among medical professionals – is the result of historic undervaluing and underfunding of women's health care.

Below the Belt aired on PBS last month is available to stream for free at PBS.org and on the PBS streaming service until July 19, 2023. Here are seven big takeaways from watching the film and speaking with Cohn.

1. Endometriosis isn't 'just bad periods'

"My first symptoms were actually GI symptoms," says Cohn, who began experiencing symptoms at the age of 16. "I ran the whole gamut of why do I have stomach aches all the time? And that's actually quite common that a lot of people with endometriosis first present with GI symptoms instead of painful periods," says Cohn.

Other common symptoms include migraines, painful intercourse, chronic fatigue, abdominal swelling, and pelvic pain throughout the cycle.

The wide variety of symptoms can make it hard to diagnose — a doctor must perform surgery to make a definitive diagnosis. It typically takes a patient anywhere from four to 10 years from first experiencing symptoms to receive an accurate diagnosis.

2. Commonly prescribed meds often do little to help

If a patient shows up at their OB/GYN's office complaining of painful menstruation or other problems that appear or worsen during their period, the doctor typically prescribes medication to suppress the hormonal cycle – often a hormonal contraceptive such as a birth control pill. These medications mitigate symptoms by allowing the patient to have a lighter period, or stop the cycle entirely.

It's important to understand that if a patient has endometriosis, hormonal medications don't actually treat the disease, says Iris Orbuch, an endometriosis specialist who appears in the film. "We're using the same medicines that have been around for about 30 years. They don't make endometriosis go away, they don't melt endometriosis," Orbuch said in the film. "But the side effects are probably worse than the benefits that the women are receiving from the medicine."

Patients interviewed for the film describe side effects including brittle teeth, hot flashes, depression and "PMS on steroids, on crack, on cocaine, and every possible stimulant."

3. A hysterectomy won't cure endometriosis. Neither will pregnancy

"Over 100,000 hysterectomies are performed every year for the disease and...most are unnecessary," says Heather Guidone, surgical program director at the Center for Endometriosis Care in Atlanta, Ga. Another common myth is that if a person with endometriosis gets pregnant, their symptoms won't return after their cycle resumes.

Guidone says the idea that both these false notions are based on an outdated theory that says if you stop periods, the disease goes away. A study of endometriosis patients who had hysterectomies and took painkillers showed no reduction in the amount of opioid and non-opioid painkillers prescribed in the three years after surgery.

Why? One theory about the origin of endometriosis is that it's the result of retrograde menstruation – meaning that during menstruation, some of the shed uterine lining travels through the fallopian tubes and implants in places where it shouldn't be. People who ascribe to this theory think hysterectomy would help but still is not a cure.

But other surgeons like David Redwine, who also appears in the film, point to evidence that endometriosis tissue actually appears during embryonic development. And so removing the uterus wouldn't affect that tissue that's been there since birth.

A hysterectomy is however the definitive treatment for adenomyosis – a disease where tissue from the uterine lining invades the muscle wall of the uterus. Adenomyosis also causes painful menstruation and infertility, and many patients have both conditions.

4. Endometriosis is responsible for up to 50% of infertility,

Another of the film's subjects is Kyung Jeon-Miranda, a Brooklyn-based artist whose paintings, featured in Below the Belt, reflect her struggles with fertility and longing for motherhood. Jeon says she was told in her early twenties that she'd never be able to conceive. But at 39, she and her husband are trying for a baby.

Endometriosis can negatively impact fertility in several ways including distorting the anatomy of the pelvis, causing scarring on the fallopian tubes and ovaries, changing the hormonal environment, and altering the functioning of the immune system. Surgery to remove endometriosis and fertility treatments may increase the likelihood of a successful pregnancy.

5. Most surgeons are doing endometriosis surgery wrong

Below the Belt subject Laura Cone, 28, of Saskatchewan, Canada, had four surgeries with general OB/GYNs. But her condition kept deteriorating, impacting her ability to drive and run her business. Laura's doctors had performed ablation – where an instrument is used to incinerate visible endometriosis tissue.

While ablation is the most common type of endometriosis surgery, it misses tissue hidden from the naked eye. Like Cone, many patients return for repeat ablations after their symptoms resume.

"I use the analogy, if you have cancer and you have a tumor, do you want someone who's not a specialist to burn off the surface of that tumor, or do you want a specialist to go in and cut it out?" the film's director Cohn says.

The gold standard method of surgery is excision, where a surgeon removes endometriosis lesions and often adjacent tissue. Studies show a greater reduction in symptoms after excision compared with ablation, and fewer patients come back for repeat surgeries.

While many OB/GYNs who see patients for routine care perform ablation, excision surgery is done by surgeons with specialized training. And many of these specialists do not accept health insurance.

As the film explains, the medical billing codes for the two types of surgery are the same – even though ablation is typically performed in under an hour, while excision can take four hours or more. "You have a whole staff who are depending on you to pay their salaries and you have to pay the light bill," says Ted Anderson, past president of ACOG, in the film. "There are a lot of economic pressures as well as do-the-right-thing-pressures."

In the film, Cone's father says he took out a second mortgage to raise the $25,000 needed to pay for his daughter's excision surgery in the U.S.

There are surgeons qualified to do excision at teaching hospitals, Cohn points out, who do accept health insurance.

6. To get proper care, patients need to take their health into their own hands.

Both Laura Cone and Jenneh Rishe learned about excision surgery from other patients on the internet. Facebook groups like Endometropolis and Nancy's Nook provide forums for patients to ask questions, compare experiences, recommend doctors, and even share surgery photos. Endometriosis specialists and nurses often answer questions in these groups as well. TikTok videos about endometriosis have over 1 billion views.

"When you're not getting the answers that you need and, and want from a health care provider, you're going to go somewhere else," says Cohn. "Of course there's misinformation everywhere and that includes online ... But you can do some digging and try to put the pieces together and learn from other people who have been in your position," she says.

Cohn also encourages patients to ask pointed questions in their doctors' appointments, especially when considering surgery. She recommends asking the surgeon if they do excision, and how frequently they perform endometriosis surgery; as well as talking to other patients who have had surgeries performed by the specialist you're working with.

In general, the earlier a patient receives excision surgery, the less they will suffer, because the symptoms tend to get worse over the female reproductive years. Endometriosis patients may find relief for their symptoms by many means, including changes to diet and exercise, and receiving massage and acupuncture. But experts say only excision surgery can halt progression of the disease.

7. A bipartisan effort is working to secure more funding for endometriosis research.

Emily Hatch, the youngest of the film's subjects, is a high school senior from Massachusetts whose endometriosis threatens her ability to attend college. In one scene, Emily's mother is on the phone with then Utah Senator Orrin Hatch – Emily's grandfather. He says he wants to help.

Emily Hatch and her mother along with Project Endo, the organization behind Below the Belt, worked with Senators Hatch and Sen. Elizabeth Warren to get $9.2 million in funding from the Department of Defense allocated for endometriosis research in 2018. After Hatch's retirement in 2019, Sen. Mitt Romney has worked alongside Warren to press for funding from the National Institutes of Health.

This March, Warren and Romney hosted a screening of the documentary before the Senate. Hilary Clinton is one of the film's executive producers.

Cohn says more research funding is sorely needed to address the disease's many unknowns. "I hope that we can do things like trying to find ... what is actually causing endometriosis. Because until we find that out, it's hard to really find ways to treat it. I hope that we can find a non-invasive diagnostic tool, so that women don't have to go years and years without understanding what is going on in their body. I hope that research can yield non-hormonal treatment options," Cohn says.

Andrea Muraskin is a podcast producer and writer living in Boston. She writes the NPR Health newsletter, and is the host and creator of the podcast LADYPARTS: Taking a Wide View on Women's Health.