Evolution demands that all species solve the equation of converting energy from the world around them into the next generation. Living things, from bacteria to blue whales, solve this equation in different and often ingenious ways based on their biology, environmental pressures, the care required for offspring to reach maturity, and even social structure. For example, some organisms reproduce asexually, some deposit unfertilized eggs that will hopefully get fertilized, and some have very long gestations, like an elephant, which carries its calf—which will ultimately weigh approximately 110 kg (243 pounds) at birth—for twenty-two months.
Reproducing a human is a massive biological effort. Energy-wise, it’s on par with the limits of the most extreme sports, for example, running 5,000 km (3,000 miles) over 120 days or cycling the Tour de France. Walking upright—being bipedal—results in a relatively smaller pelvis, which makes for a physically challenging and sometimes physically traumatic delivery, considering the relatively large head of a human fetus. Human infants are relatively helpless, a phenomenon known as secondary altriciality, so they require a significant amount of care, including breastfeeding, which is also metabolically demanding, and our ancestors had no choice but to pay this metabolic price and provide that physical care.
For humans, the platform that orchestrates turning this energy into offspring is the menstrual cycle, a unique trait seen in only a few species. To make human reproduction work, half the population needs to have a highly specialized biology that can be, repeatedly, hormonally rewired for a potential pregnancy, as well as bleed hundreds of times and each time repair itself without scar tissue. And while biologically this is an evolutionary marvel, it’s also a source of aggravation, pain, and suffering for many, because retrofitting a body for a potential pregnancy and then bleeding for several days four hundred or so times over a lifetime can have medical con­sequences. At times it can be a faulty system, but individual discomfort or injury isn’t evolution’s concern, and in fact, evolution’s motto might be best summed up as “good enough.”
Unfortunately, instead of a world where those who bear the physical burdens of reproduction—whether they reproduce or not—have equal footing, we have the opposite. The Ancient Greeks, the originators of Western medicine, labeled the female body as inferior, and the act of menstruation has been viewed as proof that women have troublesome physiology and are by nature dirty and toxic. Many religions and cultures have long carried that same torch based on the erroneous belief of impurity and the idea that men­strual blood is filthy and contains actual toxins that poison the body (and especially men, if they were to touch it). Women have been banned from places of worship, from preparing food, from having sex, and even from their own homes based on the supposed polluting powers of menstrual blood. And lest we think that was the medicine of yore, there was more than one letter published in 1974 in The Lancet, a leading medical journal, hypothesizing that there might be sound medical beliefs to support the notion that menstrual blood was toxic and that menstruating women could wilt flowers. I know, 1974!
I just can’t get my head around the concept of believing that menstruating women could wilt plants. If this were true, it wouldn’t be a curse; it would be a weapon. After all, if they could, wouldn’t they have used that power to lay waste to entire crops, bringing kings, emperors, and governments to their knees? Yet the fact that no woman has ever done this, or even used magical plant-wilting abilities to own a little land of her own, was not proof enough of its absurdity. But that is the patriarchy: facts are irrelevant; it’s the world order that matters.
As women were long viewed as lesser and more troublesome versions of men, the idea that their differences might be important and might warrant specific study to offer them better care was largely absent from medicine.
What happened instead was that medicine was created for men and then retrofitted poorly for women. For many years, studying the reproductive tract mattered mostly for improving pregnancy outcomes, rather than improving the lives of those who lived with those reproductive tracts. It wasn’t until 1993 (yes, 1993) that including women in medical studies became a requirement for government-funded research in the United States. And diseases unique to the reproductive biology attached to ovaries and a uterus are woefully under­funded compared with diseases that more commonly affect the other half of the population. We can blame medicine, and we should, but our governments provide the funding for much of this work.
The practice of viewing female physiology as both toxic and lesser through­out the ages has left a damaging legacy of inadequate research, dismissal by a patriarchal medical system, an uncaring society, and insufficient education about how the female body works. The consequences are that people struggle to get care, and the gaps in medicine are subsequently exploited by a rogue’s gallery of medical charlatans from the wellness industrial complex. When I scroll Instagram or TikTok, I’m horrified at the disinformation about the menstrual cycle and associated medical conditions that is perpetually prop­agated. There are creators claiming that menstrual blood can tell you about hormone levels, or that a “normal” period is less than three days in length and painless, or that eating raw carrots daily is essential to detoxifying dangerous estrogens, or that menstrual blood can be used as a face mask to treat acne because it has stem cells and special “healing” chemicals. To someone who knows science, this all comes off as ignorance masquerading as confidence. Look: if menstrual blood had magical healing powers, the vagina and vulva would age at a slower rate, courtesy of four hundred or so regenerative “menstrual spa” therapies.
The truth is, many people haven’t received enough information to distin­guish medicine from mythology, and disinformation is often simple and sexy, so it sells. Offering seemingly simple solutions is easy when you aren’t con­strained by facts or the truth. And let’s be clear here: almost every claim offered by these menstrual charlatans is unstudied and unregulated, which is the antithesis of feminism. Feminism demands bodily autonomy, and that can be achieved only with facts. You cannot make an empowering decision about your health when the information you have been given is false. Lying about the body is a hallmark of the patriarchy, and no amount of wrapping it with a pink bow or abusing words like natural can change that fact.
The best strategy, whether it’s dealing with a dismissive medical provider or sorting through endless menstrual misinformation on Instagram or TikTok, is a robust education, and that is the purpose of this book. I want you to have a solid knowledge of the menstrual cycle and the medical conditions and therapies associated with that cycle so you can be empowered.
I’ve been a gynecologist since 1995, and I’ve seen a lot of change during that time. We have amazing new therapies that weren’t possible when I trained and in my early years of practice. When I attended medical school in the 1980s, the idea that the human papillomavirus (HPV) caused cervical cancer was just a hypothesis, and now we can prevent cervical cancer with a vaccine against HPV. We now know so much more about so many conditions. I’ve also seen things that should have changed remain sadly stagnant. Research is slower than it should be, many people still struggle to access quality care, politicians in many parts of the world are still weaponizing reproductive health for political gain, and social media provides a playground for disinformation.
For me, the answer to advocating in the doctor’s office, or insisting our political leaders do better, or sifting through the misinformation on social media, is to provide a source of quality information. I think back to my own experiences. I suffered from terrible menstrual diarrhea (yes, there is no good menstrual diarrhea, but while the qualifier might seem unnecessary, if you’ve had menstrual diarrhea, you get it). I thought I was uniquely broken because no one ever discussed this, not even Judy Blume. It wasn’t until I was a medical student, when we had a lecture about prostaglandins and I learned they could cause diarrhea and were released during menstruation, that I had my light-bulb moment. I wanted to stand up and scream, “SAY WHAT NOW?” Of course period diarrhea was a thing! I raced down after the lecture to ask the professor if the two might be connected, and his answer made it clear that he hadn’t really thought about it, but yes.
I promptly negotiated my way into the OB/GYN clinic, scooped up some sample packs of oral contraceptive pills, and by the next cycle was as close to menstrual nirvana as possible—minimal cramping and diarrhea. The next year in medical school, I learned you could take the pill every day and not have a period, and like magic, my periods were gone—except it was courtesy of medical research and some ingenuity on my own part. Before starting the pill, I had to plan my life around my menstruation, because when the diarrhea was bad, I might need a bathroom fifteen times a day. Now I could just live my life.
There are several important take-home messages here. The first is that knowledge about my body and the available medications allowed me to make an informed decision and act on it. The second is that having quality knowledge about the menstrual cycle since age twenty, when I started medical school, meant I was essentially immune to the disinformation found every­where, so I had nothing to unlearn. And the final one is the tenacious nature of menstrual shame. When I later found out that menstrual diarrhea affects 12 percent of people who menstruate, I was stunned. This phenomenon has at times ruined my life. Once, before my hormonal contraception era, I was lucky enough to go to New York City and visit the Metropolitan Museum of Art, but I spent the entire time in the bathroom with menstrual diarrhea. Why did I have to wait until I was in medical school to find out that I suffered from something that was common and could be treated? Why did I have to wait so long to find out that I was not in this alone?
Even now, when I mention menstrual diarrhea in a lecture (and you bet I do: letting everyone know about this phenomenon has become one of my missions), there’s always someone who approaches me afterward to tell me they thought they were the only one. Same thing when I post on social media: I get direct messages from people who thought they were alone in this. How’s that for gaslighting? Six percent of the world’s population will at one point in their lives experience menstrual diarrhea (when everyone is counted, those who menstruate and those who don’t), but it’s still something few people know about? And yet 8 percent of Americans have asthma, and I’m sure every person old enough to read this book has heard of asthma.
One of my favorite experiences is when people who have read either The Vagina Bible or The Menopause Manifesto tell me they found the information enlightening and empowering. I hear stories of how people advocated for an IUD, got physical therapy to treat pain with sex, or weren’t afraid to start vagi­nal estrogen because of words I wrote. That’s why I am writing this book—not just for diarrhea education, of course, but for all of it. Because if you have or have had a menstrual cycle, or you know someone who menstruates, or you have benefited from menstruation, you should know about it. (Let’s be real: everyone has benefited from menstruation; otherwise, you wouldn’t be alive to read this book.) And if your menstrual cycle is troubling you, I want you to understand the science behind it and the therapies that are available so you can be empowered and advocate for yourself when needed.
The menstrual cycle really is the wheel that drives humanity, and it’s time to kick shame and lack of knowledge about it to the curb.