This Book Wants You To Think About Periods

Much of what we know about menstruation is wrong is because of societal biases. Kate Clancy hopes that her book will shed light on the truth.

The following is an excerpt from Period: The Real Story of Menstruation by Kathryn Clancy.

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Period: The Real Story Of Menstruation


There were a few key things I learned about periods as an adolescent. From fifth-grade health class, I learned that menstruation signaled a failed menstrual cycle with no baby. From my pediatric nurse practitioner Dr. Debbie, I learned that periods make you iron deficient. And from the world around me, I learned that I must hide all signs that I menstruated or face deep, crushing shame. This last lesson led to my acquiring the ability to plaster a smile on my face while passing a clot and developing an obsessive habit of checking to make sure no menstrual blood is visible anywhere on my body.

That warning from Dr. Debbie imprinted itself on me as well, to the point that as a young adult I went down a rabbit hole reading as much as I could about iron and menstruation. It even motivated a small project I undertook as part of my dissertation in graduate school. Using samples from my fieldwork in rural Poland, I performed an analysis comparing my research participants’ endometrial thickness (an ultrasound measurement of how much endometrium, or uterine lining, you have) with their red blood cell and hemoglobin levels (both indicators of iron status). What I found was the opposite of what was medically assumed: the thicker your endometrium, the better your iron status.1

This would be the first of many moments when I noticed an assumption about periods that, with even the gentlest of prodding, completely disassembled. And I could not help but also notice that underlying these assumptions was a certain belief about what people, organs, or processes carry scientific importance, especially in my discipline of anthropology. The origin stories in my field include such winning narratives as “White people are the pinnacle of the human race,” and “Men were the hunters and their behavior drove all of human evolution.” There were anthropologists already contesting these narratives by the time I was in college and graduate school, but even thoughtful critiques were met with contempt by many whom I read in the literature and met at conferences. I had one professor who only assigned women anthropologists in his one “feminist” week of the semester, but we had to read these works alongside scornful critiques. In my reflection assignment that week, I wrote that it seemed like he was setting up these authors to be mocked. In response, he read my comments aloud to the class and laughed. That moment created in me my own personal spite project to prove a different type of science is possible—that someone like me, asking the questions I ask, could be a professor. A PhD and a stint teaching college composition later, and I became a professor through a combination of fortune and privilege. I’ve been studying menstrual cycles off and on ever since.

When I decided I wanted to write this book, I was years deep into a different spite project that had grown to epic proportions: someone dared to tell me that uncovering discrimination in the sciences was a “witch hunt.” It started with a collaboration to study sexual harassment in the field sciences, which led to additional projects in astronomy and the planetary sciences, then undergraduate physics, and then a major consensus report, testifying in front of Congress and flying all over the country for a year disseminating the results of the report.2

As a survivor of sexual trauma multiple times over, the work I was involved with was challenging. I was fueled by it, but I also hated it. I developed vicarious trauma from all of the stories of assault, harassment, and discrimination I absorbed as both researcher and advocate, and it seeped into and mixed with my own experiences. I started heavily compartmentalizing my work and home life. While there were many wins, there were too many losses: most frustrating was realizing the changes institutions needed to make were not the ones they wanted to hear about. They wanted to sponsor a few talks, add online training. I wanted them to overhaul the incentive structures that permit bad behavior and stop thinking so short term with their risk management.

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After the birth of my second child, I struggled to see any physical touch as kindly intended (except from my infant, barely). Men were looming and frightening, even my own partner. Therapy got me clear enough on things to realize I needed to extricate myself from sexual harassment research and advocacy work, at least for a time. All I wanted to do was get back to the whole reason I became an anthropologist and study periods again.

The timing of the creation of this book and my sabbatical the year after my second child was born saved my life. I wanted to be a nerd again. I wanted to read about spiral arteries. I wanted to look at ultrasounds. Like so many of the sexual harassment survivors I’ve interviewed over the years, I just wanted to get back to my science. This project allowed me to go back to being the academic who eagerly shares how tissue remodeling works in the uterus to friends, family, and strangers. I started a podcast as an excuse to interview all sorts of dream guests who could teach me even more.

At the same time, in getting back to menstruation science I also found I couldn’t write a straight science book. It was impossible, not just because in writing about menstruation I found I could not escape the eugenic history of anthropology and gynecology or even how that history reverberates and affects reproductive justice in the present. It was because there are far more interesting questions to ask, wondrous and curious and weird things to explore, when we are able to step away from how the historical study of menstruation and menstrual cycles has shaped our knowledge. There are waves of competition between ovarian follicles.3 There are muscle contractions that ripple up and down the uterus.4 There are crypts in the cervix that store sperm for when the uterus feels like using them.5 There are chemicals in menstrual fluid that help repair tissue.6

Menstruation is a wild process that should captivate and delight. It offers up so many lessons in terms of how we understand bodily autonomy, sexual selection, even tissue engineering. It is strange, then, that instead of being something so fundamental to science education as Mendel’s peas or dinosaur bones or the planets of our solar system, it gets at best a brief mention in health class. Because of the history of how knowledge is produced, disseminated, and used in dominant culture, two things have happened instead. Within science and especially medical structures, knowledge is power and therefore often withheld; within political structures correct knowledge is rarely the point. Fertility control has been on the agenda in gynecology and in politics for decades, if not centuries. So we know little about menstruation, and what’s worse, what we often know is wrong.

On the one hand, much of the reason why what we know about menstruation is wrong—why we characterize it as burdensome or disgusting—comes from legacies of colonialism, racism, and sexism that pervade science, as I will soon show. Maybe by the end of this book, you might feel a little less revolted, a little more friendly, about periods. On the other hand, that does not mean the goal of this book is to show you the histories and subjectivities of menstruation science so you will make any different decisions about your body. With this book I want you to be able to cast your eyes upward, at the systems that persist in putting limits on better understanding, caring for, and treating bodies who menstruate. There will be marvels; there will be pointed critiques. There will not be instructions for IUD self-removal.

Excerpted from Period: The Real Story of Menstruation © 2023 by Kathryn Clancy. Reprinted by permission of Princeton University Press.

Meet the Writer

About Kate Clancy

Kate Clancy is the author of Period: The Real Story of Menstruation, and is based in Urbana, Illinois.