Another Woman’s Trash is Another Person’s Treasure: The Hidden Value of Menstrual Blood

Every teenage girl has felt the unhappiness that comes with a period. It may be because of the dreaded cramps and mood swings, the weird midnight cravings, or feeling uncomfortable and exhausted, especially during school. But for most people, it’s because of the shame. Since the beginning of civilization, menstrual cycles have been shamed in one way or another. Most of this stigma, referred to scientifically as period stigma, stems from early religions, where menstruation was seen as unclean and people avoided menstruating individuals, isolating the woman even more. To most women and girls, this stigma manifests in everyday life through ways as small as a parent asking if you’re on your period due to mood swings or as large as a lack of access to menstrual products and education due to such prominent social stigma in one’s country. Due to these factors, many feel embarrassed when their period comes and wait with the utmost excitement for it to finally end. However, the cells making up this “burden” have recently been discovered to have the potential to become crucial in medicine.

The menstrual cycle, also known as menstruation or more commonly as a period, is the monthly shedding of the uterine lining. Menstrual blood flows from the uterus to the cervix and eventually exits the body through the vagina. A typical cycle lasts about 24 to 38 days and is regulated by the feedback loops of the hypothalamus and pituitary glands of progesterone, estrogen, and follicle-stimulating hormone.

Biologist Caroline Gargett, when looking at old endometrial cells from a hysterectomy, the process in which the uterus and sometimes cervix are removed, noticed that the cells she had cultured by growing them in a controlled environment outside of their natural habitat looked like adult stem cells, undifferentiated cells that self-renew and can become any cell in the body, one type with a whisker-like shape and the other flat and round. Such cells can be transplanted and are being researched to see if they can adapt to the body in any condition or can form new tissues, which can aid in transplants, disease treatments, and vaccine creation. Despite the extraordinary potential of these cells, they are extremely hard to obtain without an extremely invasive procedure due to their existence in low numbers throughout the body. This makes Gargett’s research so revolutionary, as menstrual cycles result in the shedding and then regeneration of the endometrium each month, making stem cells found in the endometrium less limited in quantity and easier to access. To test her hypothesis, Gargett and her team at Monash University in Australia put the cells through a series of tests that evaluated the cells’ ability to self-renew and proliferate. They discovered that the cells could multiply and turn into endometrial tissue, but only the whisker-like cells, known as endometrial stromal mesenchymal stem cells (MenSCs), were multipotent, meaning they could morph into a limited number of cell types. Besides this, MenSCs also secrete bioactive molecules that promote tissue repair and regeneration by reducing inflammation, reducing fibrosis, and increasing growth factors. These properties can help treat strokes, myocardial infarction, and degenerative diseases, bringing scientists a step closer to possible medical advancements.

In addition to its potential to regenerate and form new cells, menstrual blood also can indicate the presence of painful and harmful diseases. Endometriosis is an often painful condition in which endometrial tissue grows outside of the uterus, most commonly near the ovaries, oviducts, and the tissue lining the pelvis. Normal endometrial tissue thickens, sheds, and rebuilds during the menstrual cycle; however, endometriosis tissue does not. This causes pelvic pain that amplifies during menstruation, making it extremely uncomfortable for women who experience this condition. Endometriosis is also associated with resulting in infertility and ovarian cancer, making it an extremely serious condition. Though 10 percent of the world’s population experiences this condition, not much is known about its causes and how to prevent it. This circumstance has been troubling for scientists like Sara Naseri, a medical student in Denmark, who was frustrated by the number of late diagnoses of all diseases patients get that reduce their chances of irreversible health damage due to a delay in treatment. After conducting research at the Stanford University School of Medicine, Naseri discovered a high correlation between cholesterol in menstrual blood and circulating blood. In other words, when there were high amounts of cholesterol in the menstrual samples they collected, there was also a high amount of cholesterol in the total circulating blood. This discovery can help women get diagnosed with diseases associated with high cholesterol including high blood pressure and coronary heart disease. Caroline Metz, a biomedical researcher at the Feinstein Institutes for Medical Research in New York, developed a way to make the diagnosis process less invasive for patients. In 2013, she launched the Research OutSmarts Endometriosis (ROSE) trial in which she collected menstrual cup samples from 22 women, eight who had endometriosis. Through this trial, Metz discovered a difference in gene regulation between the women who had endometriosis and those who didn’t. Those who had endometriosis had a significant decrease in uterine natural killer cells (uNKs), a type of immune cell, in comparison to the other women. Metz also found that there was an impairment in decidualization response between mesenchymal stromal fibroblast cells, a group of mesenchymal cells similar to MenSCs, which play an important role in initiating pregnancy, when compared to the other women as well. The decidualization response is a hormonally driven differentiation response that is critical in successful pregnancy establishment. The impairment of this response prevents the differentiation of these cells, hindering the development of a successful pregnancy and causing the infertility associated with endometriosis. In addition to this, she conducted a similar study in which she analyzed the genes in the endometrial tissue of the menstrual blood of 33 different women. Those with the disease had extremely low numbers of uNKs and decidualized stromal cells as well, correlating with the results of the ROSE trial. Instead, those with endometriosis had an abundance of pro-inflammatory stromal cells, which are types of stem cells that increase inflammation, causing discomfort and pain. By measuring the amounts of each cell in a woman’s menstrual blood, scientists could begin to infer the presence of endometrial tissue and make diagnoses at earlier times.

This new research proves extremely useful not only to women and girls who experience periods, but everyone and anyone. While multipotent stem cells like MenSCs aren’t as powerful as totipotent cells, which can morph into any cell type or even a whole organism, being capable of transforming into some cell types is better than none. This means when transplanted, the cells can easily adapt to the environment they are placed in, whether it be muscle or digestive cells. As with any type of stem cell, these stem-like cells can contribute significantly to scientific research. Menstrual blood also indicates health, as the correlation between cholesterol, immune cells, and menstrual blood cells Naseri noticed inspired her to start Qvin, an app which aspires to collect menstrual pad samples, analyze them, and put them into a chart the user can easily interpret, allowing them to track their symptoms and be more educated about their health. It’s also suggested that menstrual blood can be used in the diagnosis of human papillomavirus, a sexually transmitted infection that can cause gential warts and is associated with cervical cancer. Menstrual blood can even indicate how the environment influences one’s health. Shruthi Mahalingaiah, an OB/GYN at the Harvard T. H. Chan School of Public Health, took inspiration from Metz’s research and has begun to research how menstrual blood can indicate the environment’s impact on someone’s health. In her early work, Mahalingaiah surveyed women living in environments with different amounts of particulate matter, solid and liquid particles in the air, and noticed a correlation between high amounts of particulate matter and irregular periods. After meeting and collaborating with Metz, she discovered that food and cosmetic products were the cause, as they contained chemicals that disrupt hormone production and regulation including phenols, parabens, phthalates, and organochlorides. 

However, the most important thing about these discoveries is that they all stem from one fact: menstrual blood is readily accessible. Gynecology, the branch of medicine that focuses on the health of the female reproductive system, is an extremely invasive field in which diagnoses mostly require the direct examination of reproductive organs, such as pap smears and mammograms, which can be uncomfortable for the women who need these exams to insure good health. Opposite of this, the menstrual cycle occurs every month and is collected through the usage of menstrual care products. This could make the field of gynecology much more comfortable for patients and doctors by reducing awkward interactions. 

Despite this, the period stigma plays a large role in why period blood has not been researched as much as it could be. Many view period blood as taboo due to society’s perception of it as an unappealing, disgusting topic. However, due to the common nature of periods and the fact that they won’t be going away anytime soon, we should begin to discuss them and how they can be used in scientific research more. After all, they have the extraordinary potential to save lives.