Written by: Nancy King Reame, RN, MSN, PhD
The new “it” biofluid may hold the key to the secrets of reproductive health and beyond.
As a former menstruating woman (not all menstruators are women, and not all women menstruate), and a reproductive scientist, the study of menses has been near and dear to my heart for decades. Back in the 70’s I collected menses in menstrual cups (yes, the Tassaway© was around back then) from my hospital nursing colleagues to study its viscosity and cellular properties for tampon-maker Kimberly-Clark. In the ‘80’s my lab conducted the studies for the consumer groups on the FDA Advisory Task Force that standardized tampon absorbency guidelines. This came at a time when toxic shock syndrome (a very rare bacterial disease) was killing young, menstruating women in stunning proportions. Sadly the cause was shown to be related to the introduction of “super”absorbent tampon materials capable of creating the optimum intra-tampon environment when combined with menstrual blood for toxin production in individuals with little immune resistance. It was a stunning and embarrassing blow to the tampon industry to discover just how little was known about the actual makeup of menses. A major femtech catastrophe before the word had even been invented.
Fast forward to the present day when period products have exploded into a billion-dollar business with options for menstruators of all ages, shapes and genders – everything from Diva© cups to menstrual discs, not to mention period underpants, re-usable pads and smart tampons. But despite these femtech innovations, much mystery remains about the actual ingredients of menses itself.
At this summer’s meeting of the Society for Menstrual Cycle Research held in Philadelphia, I gave a flash talk, co-authored with Tulipon’s inventor Hilla Shaviv, on the new science of menstruation (everything you always wanted to know in under 8 minutes!). SMCR is an international, multidisciplinary organization made up of academics and students mostly in law, public health, and the social sciences as well as artists and menstrual activists dedicated to shaping and promoting woman-centered and gender-sensitive research and health policy agendas (www.menstruationresearch.org
Despite the intense social stigma and taboos that have plagued menstruators for generations, periods are finally having their moment, thanks not only to the recent explosion of international menstrual activism, but also to some exciting scientific discoveries that hold promise for reducing serious diseases for half of the world’s population. It turns out that next to poop, menses is becoming the new “it” biofluid for use as an important window into health and well-being. Rather than viewing menstruation merely as the body’s way of disposing unnecessary waste at the end of an infertile cycle, scientists are seeing this poorly understood process through a new lens – one that reconsiders theories about menstruation and its potential role as a tool in modern medicine.
You might wonder why study menses??
There are at least 3 good reasons why researchers are finally taking an interest in the science of menstruation:
- Menses may serve as a natural liquid biopsy to provide new biomarkers for an earlier diagnosis of some daunting uterine conditions like endometriosis, pregnancy loss and cancers. Unlike a tissue biopsy, there would be no costly, risky, painful or inconvenient medical intervention required to retrieve a specimen. And when collected over several days during a single period, or from cycle to cycle, it could provide a more accurate clinical picture, rather than just a momentary snapshot before undertaking an invasive procedure.
- As evidenced by the work of nurse-epidemiologist Kristen Upson at Michigan State University, there is a growing interest in using menses to monitor environmental hazards, as well as toxic ingredients in period products, including naturally-sourced tampons.
- Perhaps most exciting is the discovery that menses may be a new source for advanced stem cell therapy for a host of illnesses beyond the reproductive system. Let me explain. Only recently have scientists begun to take a deeper dive into the biology of menstruation and to appreciate the importance of the menstruating endometrium as a unique physiologic model of a biologic tissue that undergoes injury, degeneration, and repair every 30 days without leaving a scar. A one-of-a-kind archetype of a “wounded” surface capable of undergoing a rapid, scar-free regeneration and a return to normal function. Starting within 48 hrs of the first menstrual shedding, it regrows some 5mm of normal healthy tissue every month for some 450 cycles over a menstruator’s life span and UNLIKE CANCER< IT KNOWS WHEN TO STOP GROWING. There is no other process in the body like it. So by learning about this unique function we can better understand when things go wrong with the endometrium – as in certain reproductive and pregnancy disorders, as well as cancers. Finally! – menstruation is getting the attention it deserves.
So what is so unique about the makeup of the mense itself ? Back when I was testing the viscosity of menses in my lab with a paint viscometer for Kimberly Clark, it was assumed that menstrual discharge was basically a waste product, composed of 50% declotted, blood along with “mucousy” vaginal secretions, and bits of dead endometrial tissue shed from the uterine wall. But it turns out that menses also contains a secret sauce of unique proteins not found in venous blood or even vaginal fluid. Out of 1000 or so total proteins that have been measured in menstrual blood, some 385 are found only in menses, making them ideal candidates as menstrual fluid biomarkers. (Indeed, the biochemistry of menstrual blood was first identified by forensic scientists who needed to differentiate it from blood found at murder scenes!). Many of these menses-specific proteins have now been characterized as growth factors and immune cells – chemicals that play roles in implantation and growth, but also inflammation – all important features of endometriosis.
The astounding regenerative capability of the uterine lining came to light in 2007 when an Australian woman scientist, Caroline Gargett, realized that the cells present in the endometrial shedding were far from dead. Rather, she discovered highly potent specialized stem cells capable of reprogramming themselves into all types of other tissues like brain, lung, and even egg cells. Even more powerful than the stem cells found in bone and umbilical cord tissue now being used in cancer research, these special cell types, called menstrual blood-derived stem cells or menSC, have demonstrated some stunning results. Using animal models with various conditions, menSC treatments have regenerated the sciatic nerve , improved lung disease (a major cause of COVID death), healed diabetic ulcer wounds, and increased IVF embryo quality in cattle. In humans, there is still much work to be done; as of 2021, a handful of clinical trials for various non-gynecologic diseases had been registered on the FDA website with mostly disappointing results. However one clinical trial in Iran using menSCs to treat severe COVID-19 patients demonstrated significant lung improvement in the treated group (Fathi-Kazarooni et al, 2022).
These breakthroughs have not gone unnoticed by the femtech industry where competition is intense to be the first to achieve a successful clinical application. One such area is the development of a menses collector or processing device that preserves and stabilizes specimens for the analysis of clinical biomarkers or the extraction of stem cells.
Although still in its infancy, the science of menstruation is rapidly accelerating its pace which can hopefully be harnessed for the benefit of peoplekind. I am optimistic that these insights will bring a new approach to eradicating period shaming – namely, by educating the public about the promising scientific power of menstrual fluid. In other words, instead of viewing period blood as a disgusting waste product, we can reframe its value to society and change the context of the culture. And in that way, just as in the case of poop, there will be less mystery, shame and social stigma.
- Menstrual products as a source of environmental chemical exposure: a review from the epidemiologic perspective. K Upson et al. Curr Environ Health Rep 2022 Mar, 9 (1): 38-52.
- Physiology of the Endometrium and Regulation of Menstruation Critchley et al, Physiol Rev 2020; 100:1149-70.
- Emerging role of Menstrual-Blood-Derived Stem Cells in Endometriosis – Cordeiro et al, Biomedicines, 2023
- Uterine Bleeding: how understanding endometrial physiology underpins menstrual health..Varsha et al Nature Reviews, Endocrinology. May 2022 vol 18: 290
- Menstrual Fluid Factors Mediate Endometrial Repair: A Review. Lois A. Salamonsen, Front Reprod Health, 2021; 21 December (3)
- Gargett CE, Schwab KE, Deane JA. Endometrial stem/progenitor cells: the first 10 years. Hum Reprod Update. 2016 Mar-Apr;22(2):137-63.
- Understanding menstrual blood-derived stromal/stem cells: Definition and properties.
- Are we rushing into their therapeutic applications? Alicia Sanchez-Mata and Elena Gonzalez-Munoz. iScience 24, 103501, December 17, 2021.
- Safety and efficacy study of allogeneic human menstrual blood stromal cells secretome to treat severe COVID-19 patients: clinical trial phase I & II. M. Fathi-Kazerooni et al. Stem Cell Res Ther 2022; 13:96.