Endometriosis affects one in 10 girls/teens and women of childbearing age, according to the World Health Organization.
Endometriosis is a painful condition where tissue similar to the uterine lining grows outside the uterus in the pelvic region, most often on the ovaries, fallopian tubes or pelvic tissue.
Despite its wide prevalence and potential to cause debilitating pelvic pain and infertility, researchers say the disease remains underdiagnosed and poorly understood.
Now, emerging research is exploring a possible link between endometriosis and microplastic exposure, raising questions about how environmental contaminants might contribute to development of the condition. The findings also underscore growing public health concerns over plastic waste accumulating in human bodies and the environment.
With nearly 200 million girls and women worldwide affected by endometriosis, experts say improving understanding of the disease — and how environmental factors may influence it — is critical for advancing diagnosis and treatment.
That’s the message Julia Froese, a senior studying environmental health sciences at UNC-Chapel Hill’s Gillings School of Global Public Health, shared at a recent conference in Charlotte. Froese presented research — currently under peer review — that investigates whether menstrual blood could serve as a noninvasive diagnostic tool for endometriosis, an alternative to laparoscopic surgery, the current standard for treatment/ diagnosis.
Her research poster at the 10th Annual NC Breathe Conference, sponsored by CleanAIRE NC, earned an award in the student research competition.
“The study is looking to create a diagnostic test that’s noninvasive, using menstrual blood to actually diagnose endometriosis,” Froese said. “So more people can get diagnosed [earlier], before they turn 30 and try to have kids, and face fertility issues that could’ve been addressed if they knew they had this condition.”
The new research builds on a 2022 study that found traces of environmental toxins, including plastic particles, in menstrual blood samples, suggesting these substances can accumulate in the uterus and disrupt reproductive processes. Other recent studies highlight another barrier: period stigma. A paper published this year found that taboos surrounding menstruation often prevent people from seeking care, delaying diagnosis for conditions like endometriosis.
Not all experts agree that menstrual blood analysis will reveal early signs of endometriosis specifically, but some see value in the approach as a broader tool for monitoring contaminant exposure.
“As many toxins are widespread and causality between toxins and endometriosis is uncertain, an annual screening might not be helpful for detecting early signs,” said Liping Feng, associate professor of Obstetrics and Gynecology at Duke University School of Medicine. “For patients in highly contaminated areas, it’s worthwhile to screen for broader concerns.”
Advancing research
As part of the project, Froese worked with Dr. Christine Metz, a professor at New York-based Northwell Health’s Feinstein Institutes of Medical Research, and co-director of the organization’s Research OutSmarts Endometriosis Study. Metz, short on specifics because the research is yet unpublished, said the team is examining how micro- and nanoplastics affect uterine health and female reproduction, with early findings showing the smallest particles may cause the greatest harm.
“The smaller plastic particles seem to have more significant effects, and they’re not typically assessed or measured,” she said.
The National Oceanic and Atmospheric Administration defines microplastic compounds as fragments smaller than 5 mm in length — about the size of a pencil eraser. Over time, they can break down into even smaller particles, known as nanoplastics, some invisible to the naked eye. These substances are believed to persist in the environment for hundreds, even thousands, of years. Because plastics are still relatively new, it’s hard to know. Metz’s research also takes a novel approach to studying the uterus by analyzing menstrual blood, which contains shed uterine tissue.
“We started this in 2013 and many people laughed at us,” she said. “It’s now becoming more common, and you’ll see more studies using menstrual blood.”
Metz said she hopes that one day assessments of endometrial health through menstrual blood analysis could become part of routine wellness visits.
“The endometrial lining is shed every month,” she said.
She also said that using the substance also has the potential to help scientists measure the effects of widespread environmental contamination.
“If there were a train derailment and terrible things were released into the environment, you could actually assess exposure through [menstrual blood],” Metz said.
Hard to track
Plastic waste is an emerging worldwide contaminant that threatens the environment as well as aquatic and human health. Oceans and waterways absorb the daily load of 2,000 garbage trucks’ worth of plastic waste — more than 25 million tons each year, according to the UN Environment Programme.
Scientists are increasingly linking these microplastic particles to human health risks. A 2023 Duke University study found a possible connection between nanoplastics and a brain protein associated with Parkinson’s disease and certain forms of dementia. Previous studies have suggested that humans ingest about a credit-card’s worth of microplastics each week, and that these particles may play a role in conditions such as inflammatory bowel disease and hormonal disruption. A 2019 study also estimated that people may inhale 74,000 to 121,000 microplastic particles each year.
In 2021, the United States alone generated between 40.1 million and 51 million tons of plastic waste. Of that amount, somewhere between 32 million and 43 million tons ended up in landfills, according to data provided by Statista, a research and marketing firm.
Closer to home, environmental groups are documenting how plastic waste shows up in North Carolina’s rivers and streams. Between 2021 and 2024, seven Waterkeeper organizations maintained 21 in-stream trash traps across the state and trained staff and volunteers to record the types and quantities of litter during cleanouts. They documented more than 150,000 pieces of debris, with plastic bottles and Styrofoam making up the majority, according to a study done in the wake of the cleanup.
“Plastic doesn’t just disappear — it breaks down into microplastics, but it doesn’t decompose into vitamins and minerals like natural materials do,” said Madison Haley, an NC State graduate student and project researcher.
That same journey — from waterways into the human body — is what researchers like Froese and Metz are investigating as they study how micro- and nanoplastics may accumulate in uterine tissue and affect reproductive health.
Metz said researchers have reliable methods for detecting microplastics, but nanoplastics — particles that may be more harmful — remain far harder to track. “We don’t yet have great ways to do that,” she said.
For more information about endometriosis, see this video produced by the Mayo Clinic.
This article first appeared on North Carolina Health News and is republished here under a Creative Commons Attribution-NoDerivatives 4.0 International License.
