Part 2: Menstrual Blood Might Just Be the Most Valuable Thing in Science
Period blood has long been considered disgusting, but research shows it might just change the future of science
Hiya!
Welcome to Part Two of this article. In Part One, we discussed some long-held taboos about the human menstrual cycle, including a few particularly wild early religious, philosophical, and scientific beliefs. I also explained how these taboos are so deeply ingrained in our culture that modern researchers receive pushback when trying to study period blood.
Fortunately, some scientists persevered, so Part Two discusses what they’ve discovered. Because it turns out that period blood contains a treasure trove of information about a menstruating person’s health and has some of the most valuable cells in science, which can teach experts more about mysterious reproductive conditions like endometriosis.
Quick Recap of the Menstrual Cycle
This section is for anyone who missed Part One or wants a refresher on how a menstrual cycle typically works. If you already know, feel free to skip to the next section.
Seven to ten days after the ovaries release an egg, the hormone progesterone tells the uterus to prepare for a possible pregnancy. In response, the uterus thickens its lining (called the endometrium) and begins a process called decidualization, which is when some of the uterine endometrial cells transform to store fats and sugar and provide nutrients for a potential embryo.
Canadian-American gynecologist, New York Times columnist, and author of the 2024 book Blood: The Science, Medicine, and Mythology of Menstruation, Jennifer Gunter, compares the process to baking a soufflé because there are precise steps and measurements to follow. More importantly, once your soufflé is baked, it “can’t be turned back into a bowl of egg whites and another of egg yolks.”
Similarly, when the endometrium completes its transformation to prepare for pregnancy, its cells can’t return to their original states to be broken down and reabsorbed by the body.
Instead, the uterus sheds the endometrium as menstrual effluent, which is the blood and discharge containing cells from the uterine lining. Then it starts the process over and does it again — every month throughout a menstruating person’s reproductive decades.
While menstruating people worldwide may curse their uterus every month during their sometimes painful periods, the fact remains that it’s an extraordinary organ.
I mean, think about it. Beyond its role in creating life, the uterus sheds its lining and then flawlessly repairs itself — and it does this roughly 400 times throughout a menstruating person’s life.
Invaluable Cells in Menstrual Effluent
The uterus isn’t the only self-healing organ we have. Other organs, such as our liver, intestines, and skin (yes, skin is an organ — and our largest one at that), also regenerate. However, while these organs renew after experiencing an external injury, the uterus regenerates after self-inflicted changes — regularly.
Some scientists, including biological anthropologist Kate Clancy, have grown curious about this exquisite and confounding natural cycle and whether menstrual effluent might be crucial in healing and rebuilding the endometrium.
In other words, Clancy wondered whether period blood might not be worthless discharge from the shedding process but have a larger, more significant purpose while still inside the body.
This idea gained more weight when researchers investigated the properties of menstrual effluent and discovered special proteins, enzymes, and, most excitingly, stem cells.
Stem cells are highly coveted because they’re the only cells in our body that can transform into over 200 specialized cells, like muscle or bone. But what makes stem cells particularly valuable to scientists are their incredible healing abilities. For instance, stem cells are used to treat conditions as severe as heart failure, blood disease, and cancer.
However, a couple of obstacles prevent scientists from utilizing these exceptional cells as much as they would like. One issue is that they can be tricky to obtain from the human body.
Researchers can collect embryonic stem cells from donated umbilical blood or embryos developed during in vitro fertilization. However, collecting stem cells from adult humans is a bit trickier because they’re primarily found in the bone marrow, heart, brain, muscles, and liver, which are not easily accessible and thus often require surgery to obtain.
The National Institute for Health points out another problem:
“There is typically a very small number of adult stem cells in each tissue, and once removed from the body, their capacity to divide is limited, making generation of large quantities of adult stem cells for therapies difficult.” As a result, “The current need for transplantable tissues and organs far outweighs the available supply [of stem cells].”
Meanwhile, hundreds of millions of humans menstruate every day — that’s a lot of free-flowing stem cells being discarded. Further, researchers discovered some remarkable things about the stem cells in menstrual effluent.
In 2022, Caroline Gargett, a biologist with The Hudson Institute of Medical Research in Australia, and her colleagues identified multiple types of self-renewing cells in the endometrium.
Of particular interest was a type of stem cell called endometrial stromal mesenchymal stem cells (EnMSCs). So far, researchers have identified nearly a dozen cell types that EnMSCs can transform into, including bone, fat, neurons, and muscle cells in our organs.
These stem cells also exist in our liver, lung, skin, pancreatic, and kidney tissues, but, as researchers point out, menstrual blood provides,
an easily accessible stem cell source that can be isolated noninvasively from female volunteer donors with no ethical obstacles, making enMSCs an abundant and easily available source with no immunological response for cell replacement therapy.”
In other words, EnMSCs can be collected privately, conveniently, and noninvasively from reproductive-aged menstruating donors up to potentially 12 times a year. Since the cells naturally exit the body during menstruation, a person doesn’t need to undergo cell replacement therapy or experience unwanted immune responses, such as inflammation from their removal. Or, as physician Sara Naseri told Maggie Oatman of Mother Jones,
“Period blood is the most overlooked opportunity in medical research.”
In Part One of this article, I described Naseri’s experience at the start of her curious adventure to study period blood. Now, I want to discuss some of what she and other researchers discovered despite the pushback they received.
Such as investigating the cells in menstrual blood and how the hidden data within them could treat diseases.
Possible Medical Uses for Menstrual Blood
As you gathered from the first part of this article, research into menstrual blood is a pioneering field that’s still in its early days. Yet scientists are already hard at work conducting clinical trials to see if the EnMSCs in menstrual effluent could aid or treat a variety of medical conditions, including severe COVID and infertility. Meanwhile, a study from 2019 found the cells help heal wounds and stimulate insulin production in diabetic mice.
Naseri and her research partner, Paul Blumenthal, a Staford OB-GYN professor emeritus and international public health adviser, published a 2019 study comparing biomarkers in menstrual blood to those from arm veins during a blood draw.
Biomarkers are cellular, molecular, or biochemical changes that provide information about a person’s health. For example, high cholesterol can be a biomarker for heart disease. Some biomarkers are simple measurements such as body weight or blood pressure, but they’re also found in our tissues and fluids and on the molecular and cellular level, such as in proteins and genes.
Blumenthal said that when he and Naseri compared the biomarkers between the two blood sources, “They were pretty much bang on.”
The study was a small pilot study, so further research is needed. However, its results are significant enough to support the possibility that monitoring periods could become an alternative testing method for major diseases — similar to a doctor running a blood panel during your annual wellness checkup, but without the needle.
Further, since menstrual blood comes from the uterus, it could be tested for cytokines. Cytokines are protein-chemical messengers in the immune system that offer insights into uterine disease and inflammation. Typically, menstruating people undergo invasive sampling or laparoscopies to test for cytokines. However, as Naseri and Blumenthal state in a 2023 study, testing menstrual blood instead could be a far less invasive option.
Even more appealing for any female during their reproductive years is the idea that testing menstrual blood could significantly reduce or completely replace Pap smears — a highly invasive, uncomfortable procedure involving undressing at a doctor’s office and hoisting your legs in stirrups while the doctor inserts a speculum and sweeps or prods the cervix to collect its cells so they can test them for any risk of cervical cancer and human papillomavirus (HPV.)
However, menstrual blood collects the same cells as the effluent passes through the cervix on its way out of the body. In other words, the body practically delivers cytokines on a silver platter.
Any menstruating person can celebrate the idea of never having another Pap smear, but especially any sexual trauma survivors for whom Pap smears can be triggering, if not impossible.
Beyond stem cells and alternative blood testing methods, research into menstrual blood is helping scientists crack the code of a particularly mysterious reproductive ailment.
Endometriosis
Endometriosis is a perplexing disease wherein tissue similar to the uterine lining, or endometrium, grows outside the uterus. Growing where it shouldn’t causes a person to experience painful, sometimes chronically debilitating symptoms that impact a menstruating person’s cycle and often their daily life. It can also interfere with a person’s fertility due to resulting scarring and blockages in the fallopian tubes.
Endometriosis affects about 10 percent of people assigned female at birth or around 190 million individuals worldwide. Researchers estimate that between treatments, loss of production, and other burdens related to the disease, endometriosis costs the United States economy and medical system up to $119 billion a year.
Yet, despite its heavy price tag and the fact that millions of people have endometriosis, it takes years and one or more surgeries (and doctors) after initial symptoms begin before people receive a diagnosis. According to the Yale School of Medicine:
“[I]t takes women 10 years to receive an accurate diagnosis of endometriosis, and many see at least four or five doctors before their pain is taken seriously.”
And it takes even longer for people of color.
Unfortunately, between its mysterious etiology, complexity, and those pesky sex and gender biases in medical research, as of now, there is no cure for endometriosis.
Quick Historical Side Quest:
By the way, endometriosis is not a new or newly discovered disease. Some suspect that reports of endometriosis go back as far as 4,000 years ago, and according to the Yale School of Medicine:
“Time and again, as far back as the age of Hippocrates, physicians have failed to recognize endometriosis as a real disease with underlying physical causes and often blamed women for the debilitating symptoms they experienced.”
A truth supported by endometriosis and fertility specialist Ceana Nezhat, who wrote in a 2012 article published in Fertility and Sterility:
“[H]ysteria, the now-discredited mystery disorder, presumed for centuries to be psychological in origin, was most likely endometriosis in the majority of cases. If so, then this would constitute one of the most colossal mass misdiagnoses in human history, one that over the centuries, has subjected women to murder, madhouses, and lives of unremitting physical, social, and psychological pain. The number of lives that may have been affected by such centuries-long misdiagnoses is staggering to consider, likely involving figures in the multiple millions.”
It wasn’t until 1860, when physician, pathologist, and philosopher Karl von Rokitansky microscopically identified endometriosis, that the scientific and medical communities started to recognize it as a disease. However, endometriosis and the people who suffered from it have remained largely ignored in the centuries since.
Anyway, as I was saying, despite its long history, expensive price tag, and the millions of people who regularly experience the painful effects of endometriosis, it’s considered a white whale for researchers.
Playing Catch-Up with Endometriosis Research
Christine Metz, a professor at the Feinstein Institutes for Medical Research at Northwell Health, told Oatman that she was “shocked” a decade ago when she learned menstrual effluent hadn’t been considered a convenient window into a female’s reproductive organs. She said that menstrual effluent is like “a biopsy of the endometrium.”
In 2013, Metz joined a team of her colleagues to co-direct a prominent endometriosis study called the Research OutSmarts Endometriosis (ROSE) study. The study has been ongoing for over a decade, and the website says it may continue “indefinitely,” making it the longest-running endometriosis study yet.
The goal of the ROSE study is to find a less invasive way to detect diseases in the body, so they compared samples of menstrual blood from women with an endometriosis diagnosis to a control group and discovered that the two groups of endometrial cells looked different.
More specifically, the endometrial cells in the effluent of people with endometriosis contained fewer biomarkers sensitive to the hormone progesterone, fewer immune cells that typically protect the uterus and are thought to play a crucial role in fertility, and more B cells, which are associated with inflammation.
While the study was small, it is a promising step toward speeding up the endometrium’s diagnostic process. Hopefully, analyzing menstrual blood can become a diagnostic alternative to invasive surgeries or biopsies.
As a matter of fact, just like Naseri was ahead of the curve when she grew curious about using menstrual blood to study female health, now, she’s at it again.
In the Future
In addition to her impressive research, Nareri is also a co-founder of the startup Qvin (pronounced" kwin”), which is derived from the Danish word for “woman.” Qvin is a biotechnology research company that collects and studies donated menstrual blood as an alternative to traditionally collected venous blood draws.
In January 2024, Qvin received approval from the US Food and Drug Administration (FDA) for its new menstrual pad, called a Q-Pad — currently on the market for $29 — and A1C (blood-glucose) testing.
The idea is that the Q-Pad, which sticks to underwear, collects the effluent of a menstruating person during their period. Afterward, the user removes a test strip from the pad to easily transport a dried blood sample.
Once the sample reaches Qvin’s labs, researchers analyze it for average blood sugar (A1C) levels, which is a biomarker for two types of diabetes. However, Naseri told Oatman that Qvin hopes to offer more test options in the future, including tests for fertility hormones and high-risk human papillomavirus (HR-HPV).
Previously, in February 2023, Q-vin secured approval to market the Q-pad in Thailand, where it was given the green light to screen for HR-HPV.
A press release about the Q-Pad suggests that the product and Qvin’s testing could help cut healthcare costs while allowing people to receive reports on “key health conditions that often go undiagnosed or misdiagnosed,” including fertility, perimenopause, and endometriosis.
As exciting as the entire Q-Pad concept may be for menstruating people, let me be clear that the product and testing are only meant to supplement regular doctor visits, not replace them.
More importantly, the Q-Pad can not be used to diagnose diseases and currently does not test for anything other than A1C in the United States.
Also, Clancy (whom I mentioned waaaay back near the beginning) cautions against capitalizing on such products too early.
Clancy, who also runs a lab studying the effects of environmental stressors on women and gender minorities, explained to Oatman that menstrual science is basically in its infantry. There’s still a lot we don’t understand about menstruation or the uterus. She said:
“I think we really need to take a step back and say, ‘Have we actually done the basic research to fully characterize this, to understand how it varies between people, how it varies with the environment, varies through the life course?’ Before we start saying, ‘We could measure this and get money for it.’”
Qvin is only one of a growing wave of research initiatives and companies jumping to explore and develop the long-dismissed, neglected, and wasted opportunities menstrual blood could provide. But I agree with Clancy that it’s still early days, and we should proceed with care.
Perspective Shift
Phew! Congratulations. Now you know just about everything I discovered while tumbling down these bewildering rabbit holes. I started with gender and sex bias in medical research related to heart disease and statins, then I learned about menstrual taboos, only to end up discovering that the very same natural process just may revolutionize the future of science.
A significant reason scientists are learning more about female health after millennia of villainization is that more women are entering science, technology, engineering, and math (STEM) fields than ever before. More diversity means more perspectives, which makes it easier to notice, recognize, and change our assumptions, biases, and beliefs — so we can learn even more about this Curious Adventure we call Life.
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The federal government should immediately sponsor major research in this field in order to benefit women. Oh, wait…