What We Still Don’t Know About Periods

In 2013, the researchers Christine Metz and Peter K. Gregersen proposed what is now considered to be one of the most important investigations in the study of endometriosis. The substance they wanted to analyze was abundant and easy to collect: menstrual blood, or “effluent,” as it’s better described, since much of this substance is not only blood but endometrial cells, hormones, and vaginal secretions. Their idea was simple. Participants would collect their menstrual flows using cups or specialized sponges, and mail the samples to their research center. There, the material would be studied for potential markers for endometriosis, a lifelong, incurable condition in which tissue similar to that which lines the uterus grows outside the womb. Endometriosis is notoriously painful and affects at least ten per cent of people with uteruses. Diagnosing the condition takes, on average, a decade, and often requires a laparoscopic procedure in which a viewing instrument is inserted, through an incision, into the abdomen and tissue is retrieved and biopsied. By testing menstrual blood, they were hoping to make endometriosis diagnoses faster, less invasive, and more accessible.

Some of their colleagues responded to their study with disgust and unease. “When we started promoting our study and trying to recruit women to the study,” Metz tells the midwife and podcaster Leah Hazard, “we found that most physicians were not going to help us. They were very reluctant to talk about the study with their patients. They said, ‘Oh, my patients aren’t going to give you menstrual effluent. No way. They wouldn’t like to do that.’ ” Medical professionals, as Hazard writes in her new book, “Womb,” are not immune to shame around periods—the embarrassment that induces menstruating people to hide tampons up their sleeves when walking to the bathroom, or experience a sense of deep mortification over a bloodstain. What she calls the “yuck factor” associated with periods leads many doctors and scientists to avoid the subject. In a review of scientific papers, Hazard finds that there are about four hundred studies on menstrual effluent compared with more than fifteen thousand for semen or sperm.

“Womb” and another new book, “Period,” by the biological anthropologist Kate Clancy, hope to draw our attention to menstruation and the often overlooked organ central to it. Both books begin by invoking the stigma associated with the female reproductive system. In her introduction, Clancy stresses the disgust she encountered when she told people she was writing a book about periods. “Sometimes it’s easier not to see, not to know,” Hazard writes, then exhorts readers to remember they are made of “sterner stuff.”

“Womb” interweaves observations drawn from Hazard’s own work in labor wards with reporting and interviews. As part of her research, she travels to Sweden to watch a uterus transplant from a thirty-seven-year-old woman who had had several children to her twenty-one-year-old sister, who has Mayer-Rokitansky-Küster-Hauser syndrome, a condition in which the uterus is underdeveloped or absent. So far, at least seventy uterus transplants have taken place globally, and the procedure may hold promise for transgender women, women born without a womb, and people who might wish to conceive but have had their wombs removed. Hazard joins a group of doctors from around the world to observe the operation. She watches as the uterus, “blanched and lifeless,” is lifted out of the donor’s body and safely transported to her sister’s. “Fresh blood rushes into the adjoining vessel and a pink blush spreads slowly across the uterus—until now, a fist of pale white muscle. I can hardly believe what I’m seeing. What was dead now has life; what was still and cold now pulses with heat.”

Hazard’s recounting of the uterus-transplant surgery is one of the rare moments we see her excited about reproductive health care. More often, it’s her exasperation that leaps off the page. Of her time working as a midwife on the postnatal ward, she writes:

I became accustomed to new mothers approaching me at all hours of the
day and night, pale and panicked, brandishing various unlikely bits of
detritus from delivery—a clot saved on a pad for examination, a stray
piece of suture material found in a gusset—but none provoked as much
alarm as the tiny nappy streaked with pink. “My daughter’s bleeding,”
they would exclaim, simultaneously embarrassed and concerned, and
often more than a little bit disgusted. What these women had noticed
was a normal, physiological process about which—like so much of female
life—nobody had warned them.

During pregnancy, a fetus is exposed to high levels of maternal hormones. The withdrawal of those hormones after birth can lead to blood-tinged discharge, resembling a period. Hazard is used to reassuring new mothers that this bleeding is perfectly normal, but she is frustrated by the need to keep having the conversation, which never fails to remind her of the shame and ignorance surrounding basic female reproductive processes.

It’s tempting to dismiss superstitions around the impurity of menstruation as drastically outdated. But, as Clancy points out, these prejudices have at times taken on a dangerous scientific veneer. In the nineteen-twenties, a doctor claimed he had discovered a substance in menstrual blood that wilted flowers. “Menotoxins,” as they came to be called, were thought to be excreted through a menstruating woman’s pores, in her sweat, and in her breast milk. The hypothesis continued to be debated seriously well into the nineteen-seventies.

Though the menotoxin theory was eventually refuted, periods continue to have noxious associations. Clancy cites one study, from 2002, in which a female actor was asked to drop either a tampon or a hair clip in front of research participants. Regardless of their gender, observers reacted far more harshly to the woman when she dropped a tampon. They liked her less, and thought her less competent than when she dropped a hair clip. They were also less likely to sit close to her after they’d seen her drop a tampon in the lab room, as if she were contaminated.

A similar aversion among scientists has likely led to a broader lack of research into the causes of menstruation. For a long time, the dominant hypothesis was that human periods were nonadaptive. Some mammals release an egg only when procreative sex seems imminent or occurs, when there is physical stimulation or certain pheromones are detected. Human ovulation, and the shedding of the uterine lining that ensues, can seem wasteful in comparison. Clancy, however, presents evidence suggesting that periods may help teach the uterus to foster a safer pregnancy for mother and fetus.

Our conception of a “normal” period may not exist outside of medical textbooks. After measuring the hormonal levels of a large sample of women in the course of their cycles, Clancy found that not a single participant’s hormones matched the standard model, in which a fourteen-day follicular phase is followed by an ovulation period and then a fourteen-day luteal phase. Though the average level of the women’s estrogen did tend to peak mid-cycle, the individual variations were striking. Some participants in the study experienced double peaks of estrogen. Others had higher estrogen levels in their luteal phases than in the middle of their cycles. For a significant number of women, Clancy writes, “traditional expectations about how a menstrual cycle is supposed to work” did not seem to apply.

The obscurity that shrouds the workings of the uterus may have had severe consequences for reproductive health. Limited treatment options for those suffering from a range of gynecological conditions contributes to the widespread use of an extreme and irreversible medical procedure: removal of the womb. Hysterectomies are the second most frequent operation for women in the United States. (The most frequent is the Cesarean section.) A third of women have their uteruses removed by the age of sixty-five. The procedure is often to remove fibroids; though this condition will afflict seventy to eighty per cent of people with uteruses in the course of their lives, it remains poorly understood. In 2001, Stephanie Tubbs Jones, a representative from Ohio, introduced a congressional bill to fund research into the condition, but it was never passed. A resurrected version of the bill, the Stephanie Tubbs Jones Uterine Fibroid Research and Education Act, died in Congress.

Research into many major pregnancy complications—miscarriage, preeclampsia, intrauterine growth restriction, and stillbirth—is also sparse. Hazard interviews Dr. Margherita Yayoi Turco, a researcher then at the University of Cambridge who was working on a placental “organoid,” tiny placental tissue that can, under the right conditions, form mini-placentas in a dish, and be analyzed for its response to different drugs and hormones. Despite the importance of placental development for a successful pregnancy, garnering support for her work was difficult. “When I came into this field, it was really clear that it was hard to find funding,” she tells Hazard. “The placenta? It’s mostly, like, ‘Who cares? We just throw it away.’ ”

A fantasy persists, in the popular imagination, of sperm as Olympic swimmers, racing toward an egg that passively awaits fertilization. Clancy and Hazard are both keen to complicate this simplistic picture of conception. Sperm are drawn in by uterine waves, Clancy asserts, “a special type of muscle contraction that helps control the speed at which sperm reach the egg, propelling them on a journey that would otherwise be too long for them to make on their own.” Hazard also emphasizes the organ’s strength. “The womb is a muscle,” she writes. “We can compare it quite accurately to a clenched fist, not only in size, but in power.”

Hazard and Clancy hope to encourage us to better appreciate this remarkable muscle. The interior of the uterus, Clancy points out, goes through a process of tissue repair month after month without leaving any scar tissue. Though the organ’s regenerative powers are not well understood, it has the potential to inform treatment of a variety of chronic wounds. A recent study indicates that menstrual effluent specifically might have healing properties. When applied to skin wounds, plasma extracted from menstrual fluid appeared to improve the repair process. Rather than greeting our periods with disgust, perhaps we should trade our revulsion for awe. ♦

Leave a Reply

Your email address will not be published. Required fields are marked *