Yentl Syndrome: A Deadly Data Bias Against Women

The science of medicine is based on male bodies, but researchers are beginning to realize how vastly the symptoms of disease differ between the sexes — and how much danger women are in.

Caroline Criado Perez | An excerpt adapted from Invisible Women: Data Bias in a World Designed for Men | Harry N. Abrams | 22 minutes (5,929 words)

In the 1983 film Yentl, Barbra Streisand plays a young Jewish woman in Poland who pretends to be a man in order to receive an education. The film’s premise has made its way into medical lore as “Yentl syndrome,” which describes the phenomenon whereby women are misdiagnosed and poorly treated unless their symptoms or diseases conform to that of men. Sometimes, Yentl syndrome can prove fatal.

If I were to ask you to picture someone in the throes of a heart attack, you most likely would think of a man in his late middle age, possibly overweight, clutching at his heart in agony. That’s certainly what a Google image search offers up. You’re unlikely to think of a woman: heart disease is a male thing. But this stereotype is misleading. A recent analysis of data from 22 million people from North America, Europe, Asia and Australasia found that women from lower socio-economic backgrounds are 25% more likely to suffer a heart attack than men in the same income bracket.

Since 1989, cardiovascular disease has been the leading cause of death in US women and, following a heart attack, women are more likely to die than men. This disparity in deaths has been the case since 1984, and young women appear to be particularly at risk: in 2016 the British Medical Journal reported that young women were almost twice as likely as men to die in hospital. This may be in part because doctors aren’t spotting at-risk women: in 2016, the American Heart Association also raised concerns about a number of risk-prediction models “commonly used” in patients with acute coronary syndrome, because they were developed in patient populations that were at least two-thirds male. The performance of these risk-prediction models in women “is not well established.”

Common preventative methods may also not work as well in women. Acetylsalicylic acid (aspirin) has been found to be effective in preventing a first heart attack in men, but a 2005 paper found that it had a “nonsignificant” effect in women aged between forty-five and sixty-five. Prior to this study, the authors noted, there had been “few similar data in women.” A more recent study from 2011 found that not only was aspirin ineffective for women, it was potentially harmful “in the majority of patients.” Similarly, a 2015 study found that taking a low dose of aspirin every other day “is ineffective or harmful in the majority of women in primary prevention” of cancer or heart disease.

Perhaps the greatest contributor to the numbers of women dying following a heart attack, however, is that their heart attacks are simply being missed by their doctors. Research from the UK has found that women are 50% more likely to be misdiagnosed following a heart attack (rising to almost 60% for some types of heart attack). This is partly because women often don’t have the “Hollywood heart attack” as it’s known in medical circles (chest and left-arm pains). Women (particularly young women) may in fact present without any chest pain at all, but rather with stomach pain, breathlessness, nausea and fatigue. These symptoms are often referred to as “atypical,” a designation to which the British Medical Journal took exception in a 2016 article, saying that the term “may lead to the under-appreciation of risk associated with this presentation.” And under appreciation of the risk may in turn explain why a 2005 US study found that “only one in five physicians across multiple specialties was aware that more women than men die from cardiovascular disease each year, and most of these physicians did not rate themselves as effective in treating sex-tailored cardiovascular disease.”

Since 1989, cardiovascular disease has been the leading cause of death in US women and, following a heart attack, women are more likely to die than men.

Atypical or not, for certain types of heart attacks, women (and again especially young women) who present without chest pain are at particular risk of death — which makes it extremely concerning that current NHS England guidelines specify “acute cardiac sounding chest pain” as part of the criteria for a patient being referred for primary percutaneous coronary interventions (PPCI) at one of the country’s specialist twenty-four-hour heart-attack centers. PPCI is an emergency treatment that restores blood flow during a heart attack, and which according to one doctor I spoke to has “massively improved survival and outcome.” But this treatment is only carried out at the twenty-four-hour heart-attack centers and, perhaps as a result, 75% of those who receive this treatment are men.

The tests doctors use to determine what’s wrong with a patient are also likely contributing to women’s higher death rates following a heart attack. Standard tests like the electrocardiogram or the physical stress test have been found to be less conclusive in women. A 2016 BMJ paper refers to recent work from Edinburgh which showed that the “normal” diagnostic threshold for troponin (a protein released into the blood during heart damage) may be too high for women. And it’s not just about “standard” levels for biomarkers being incorrect in women, we also need to establish new female-specific biomarkers. A biomarker is a biological characteristic (like troponin) whose presence can act as a diagnostic criteria for a specific disease, and a 2014 literature review of sex difference studies suggests that this may be a fruitful area to research. Unfortunately, it concludes that the work done so far is too limited to be able to say whether or not female-specific biomarkers will be found.

Because women’s heart attacks may not only present differently, but may in fact be mechanically different, the technology we’ve developed to search for problems may not be suitable for female hearts. For example, a heart attack is traditionally diagnosed with an angiogram, which will show where there are obstructed arteries. But women often don’t have obstructed arteries, meaning that the scan won’t show up any abnormalities, and women who turn up at hospital with angina (chest pain) may simply be discharged with a diagnosis of “non-specific chest pain” and told they have no significant disease. Except they do: women with “normal” angiograms have gone on to suffer a heart attack or stroke shortly after being discharged from hospital.

Assuming a woman gets lucky and has her heart disease diagnosed, she must then navigate the obstacle course of male-biased treatment: sex differences have not generally been integrated either into “received medical wisdom” or even clinical guidelines. For example, say a man and a woman are both diagnosed with a swollen aorta (the aorta is the main blood vessel that runs from the heart down through the chest and stomach). They are both suffering from an equal level of swelling — but their risk is not the same: the woman has a higher risk of rupture, which carries with it a 65% chance of death. And yet, in Dutch clinical guidelines, the thresholds for surgery don’t differ for each sex.

Diagnostic tests developed around male bodies are also a problem in other medical disciplines, even those where women are more at risk. Women have a higher risk than men of developing right-sided colon cancer, which often develops more aggressively, but the fecal blood test commonly used to detect colon cancer is less sensitive in women than in men. Meanwhile, because women have on average a longer and narrower colon than men, colonoscopies in women may be incomplete. Then there’s what the WHO calls the “frequent mistake” of underestimating the importance of symptoms that can only occur in one sex, such as vaginal bleeding in dengue fever. When symptoms are listed in order of frequency for all patients rather than separated by sex, female-specific symptoms can be presented as less significant than they are in reality.

The impact of such data gaps can snowball. When it comes to tuberculosis (TB), for example, a failure to account for how female social roles could make the disease more dangerous for women combines with a failure to collect sex-disaggregated data, leading to potentially deadly consequences. Men are more likely to have latent TB, but women are more likely to develop the active disease. Studies also suggest that women in developing countries who cook in poorly ventilated rooms with biomass fuels (that is, means millions of women) have impaired immune systems which leave them less able to fight off the bacteria. The result is that TB kills more women globally than any other single infectious disease. More women die annually of TB than of all causes of maternal mortality combined. But TB is nevertheless often considered to be a “male disease,” and as a result women are less likely to be screened for it.

Even when women are screened, they are less likely to be diagnosed. Women may have a different immune response to TB resulting in different symptoms, and one study on why women are misdiagnosed found that TB lung lesions might not appear as severe in women. There is also evidence of sex differences in the sensitivity of commonly used screening tests. The standard way to test for TB in resource-limited settings is to get patients to cough up sputum and examine it under the microscope. But women with TB are less likely to have a sputum-producing cough, and even if they do have one their sputum is less likely to test positive for the disease. The sputum test is also problematic for social reasons: a study in Pakistan reported that women felt uncomfortable coughing up the mucus needed for the examination, and health workers weren’t explaining why they needed to. So they didn’t.

Medical practice that doesn’t account for female socialization is a widespread issue in preventative efforts as well. The traditional advice of using condoms to avoid HIV infection is simply not practicable for many women who lack the social power to insist on their use. This also goes for Ebola, which can remain present in semen for up to six months. And although a gel has been developed to address this problem, it fails to account for the practice of “dry sex” in certain parts of sub-Saharan Africa. A gel which also acts as a lubricant will not be acceptable in areas where women de-lubricate their vaginas with herbs in order to indicate that they are chaste.

Failing to account for female socialization can also lead to women living for decades with undiagnosed behavioral disorders. For years we have thought that autism is four times more common in boys than in girls, and that when girls have it, they are more seriously affected. But new research suggests that in fact female socialization may help girls mask their symptoms better than boys and that there are far more girls living with autism than we previously realized. This historical failure is partly a result of the criteria for diagnosing autism having been based on data “derived almost entirely” from studies of boys, with a 2016 Maltese study concluding that a significant cause of misdiagnosis in girls was “a general male-bias in diagnostic methods and clinical expectations.” There is also emerging evidence that some girls with anorexia may in fact be suffering from autism, but because it’s not a typical male symptom it’s been missed. Sarah Wild, head of Limpsfield Grange, the UK’s only state-funded residential school for girls with special needs, told the Guardian that “the diagnostic checklists and tests have been developed for boys and men, while girls and women present completely differently.” Meanwhile, a recently published draft of new NHS guidance on autism made no mention of women’s differing needs.

There is also emerging evidence that some girls with anorexia may in fact be suffering from autism, but because it’s not a typical male symptom it’s been missed.

There are similar diagnostic problems when it comes to attention deficit hyperactivity disorder and Asperger’s. A 2012 survey by the UK’s National Autistic Society found that just 8% of girls with Asperger’s syndrome were diagnosed before the age of six, compared with 25% of boys; by the age of eleven the figures were 21% and 52%, respectively. Up to three-quarters of girls with ADHD are estimated to be undiagnosed — a gap which Dr Ellen Littman, the author of Understanding Girls with ADHD, puts down to the early clinical studies of ADHD having been done on “really hyperactive young white boys.” Girls tend to present less as hyperactive and more as disorganized, scattered and introverted.

More broadly, researchers suggest that because women are socialized to “take turns in conversation, to downplay their own status, and to demonstrate behaviors that communicate more accessibility and friendliness,” the traditional medical interview model may be unsuccessful in getting the information from women that is needed to diagnose them effectively. But sometimes — often — women are providing the information. It’s just that they aren’t being believed.

American news website ThinkProgress reported the story of Kathy, whose heavy periods left her feeling so faint she couldn’t stand. But when it came to getting a diagnosis, Kathy faced a problem: four different medical professionals thought it was in her head, that “she was simply struggling with anxiety and perhaps even had a serious mental health disorder.” Her primary-care doctor went so far as to tell her more than once, “All your symptoms are in your imagination.”

But they weren’t in her imagination. In fact, Kathy turned out to have “potentially life-threatening uterine fibroids that required surgical intervention,” something that was only discovered after she demanded an ultrasound. She wasn’t anxious (although after nine months of being told she was crazy who could blame her if she was), she was anemic.

Rachael was also told she was imagining it. She had been trying to manage her severe pain and heavy periods with the pill for ten years by the time she collapsed at a gig. The hospital sent her home with painkillers and a diagnosis of stress. The next time she collapsed the hospital put her in the gastroenterology ward. “Six nights I was there, on a drip. There was a woman dying of bowel cancer in the bed opposite me. It was horrible.” The doctors suspected kidney stones, so they ran multiple tests around her urinary system. They all came back negative. So did her blood tests. And the more tests that came back negative, the more Rachael sensed a shift in how she was being treated. “I started feeling they weren’t believing me. That they thought it was all in my head.” Eventually a consultant shook his head as Rachael told him how much she hurt and told her, “We have to send you home. There’s nothing wrong with you.”


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But there was something wrong with her. Rachael was eventually diagnosed with endometriosis, a disease where womb tissue grows elsewhere in the body, causing extreme pain and sometimes infertility. It takes an average of eight years to diagnose in the UK, an average of ten years to diagnose in the US, and there is currently no cure. And although the disease is thought to affect one in ten women (176 million worldwide) it took until 2017 for England’s National Institute for Health and Care Excellence to release its first ever guidance to doctors for dealing with it. The main recommendation? “Listen to women.”

This may be easier said than done, because failing to listen to female expressions of pain runs deep, and it starts early. A 2016 study from the University of Sussex played a series of cries to parents (twenty-five fathers and twenty-seven mothers) of three-month-old babies. They found that although babies cries aren’t differentiated by sex (sex-based pitch differences don’t occur until puberty) lower cries were perceived as male and higher cries perceived as female. They also found that when male parents were told that a lower-pitched cry belonged to a boy, they rated the baby as in more discomfort than when the cry was labelled female.

Instead of believing women when they say they’re in pain, we tend to label them as mad. And who can blame us? Bitches be crazy, as Plato famously said. Women are hysterical (hystera is the Greek word for womb), crazy (if I had a pound for every time a man questioned my sanity in response to my saying anything vaguely feminist on Twitter I would be able to give up work for life), irrational and over emotional. The trope of the “crazy ex-girlfriend” is so common it’s been satirized by Taylor Swift in her hit song “Blank Space” and by Rachel Bloom in a whole Netflix series about a Crazy Ex-Girlfriend. Women are a “mystery,” explained renowned physicist Stephen Hawking, while Freud, who got rich and famous off his diagnoses of female hysteria, explained in a 1933 lecture that “Throughout history, people have knocked their heads against the riddle of femininity.”

The intransigence of this feminine riddle has not gone unpunished. Women who had often done little more than manifest behaviors that were out of feminine bounds (such as having a libido) were incarcerated for years in asylums. They were given hysterectomies and clitoridectomies. Women were locked up for having even mild post-natal depression: the grandmother of a friend of mine spent her life in an asylum after throwing a scourer at her mother-in-law. At least one US psychiatric textbook, still widely in use during the 1970s, recommended lobotomies for women in abusive relationships.

Of course, weve moved on from such inhumane treatment of women. We no longer lock women up and cut out parts of their brains. Instead, we give women drugs: women are two and a half times more likely to be on antidepressants than men. This is not to condemn antidepressants: they can be life-changing for people with mental health problems. However, it’s still worth asking why women are so much more likely to be on them, because it’s not simply that women are more likely to seek help. A 2017 Swedish study in fact found that it was men who were more likely to report depression. So why are more women being treated with antidepressants? Are women simply more “feeble-minded”? Does living in a world in which we don’t quite fit affect our mental health? Or are antidepressants the new (and obviously preferable) lobotomy for women dealing with trauma?

Freud once believed that hysteria might be linked to historic sexual abuse. He later retracted this theory as it would have implicated too many men to be, in his opinion, credible. But recent research suggests that abuse might be linked to certain types of pain women experience — and in the wake of the #MeToo global scandal maybe it’s not so incredible after all.

The full answer to these questions is beyond the scope of this book. But one possible explanation for at least part of the disparity is that women are being prescribed antidepressants when they are not in fact depressed. Women’s physical pain is far more likely to be dismissed as “emotional” or “psychosomatic.” The Swedish study which found that men are more likely to report depression also found that women who have not reported depression are twice as likely as men to be prescribed antidepressants. This chimes with studies from the 1980s and 90s which found that while men who reported pain tended to receive pain medication, women were more likely to receive sedatives or antidepressants. A 2014 study which required healthcare providers to make treatment recommendations for hypothetical patients with lower back pain similarly found that female patients were significantly more likely to be prescribed antidepressants than men.

Women no longer have more active years than men, despite their longer lives.

It seems that Yentl syndrome may be at play again here: it is striking that so many of the stories women tell of undiagnosed and untreated pain turn out to have physical causes that are either exclusively female diseases, or are more common in women than in men. Women are almost twice as likely to have irritable bowel syndrome as men and three times more likely to experience migraines (a condition about which we know very little despite it being chronic, often deeply debilitating and affecting 37 million Americans and one in eight people in the UK). In fact, many clinical pain conditions are substantially more prevalent in women than men, and several studies over the past decades have shown that women are more sensitive to pain than men (which sheds a particularly cruel light on the finding that women are less likely to receive painkillers). There is also mounting evidence that men and women may experience pain differently. A woman’s pain sensitivity increases and decreases throughout her menstrual cycle, “with skin, subcutaneous tissue, and muscles being affected differently by female hormonal fluctuations.” An animal study which found that males and females use different types of immune cells to convey pain signals may provide the beginnings of an answer as to why — although only the beginnings: sex differences in pain remain an under-researched area and even what we do know is not widely dispersed. Dr Beverly Collett, who until she retired in 2015 was a consultant at Leicester’s pain management service and chair of the Chronic Pain Policy Coalition, told the Independent that the average GP “has no idea that drugs such as paracetamol and morphine work differently in women.”

Even if they are treated for their pain, women routinely have to wait longer than men to receive that treatment. A US analysis of 92,000 emergency-room visits between 1997 and 2004 found women had longer waiting times than men, and a study of adults who presented to a US urban emergency department between April 2004 and January 2005 found that while men and women presented with similar levels of pain, women were less likely to receive analgesia and women who did receive analgesia waited longer to receive it. A US Institute of Medicine publication on chronic pain released in 2011 suggested that not much has changed, reporting that women in pain face “delays in correct diagnosis, improper and unproven treatments,” and “neglect, dismissal and discrimination” from the healthcare system. In Sweden a woman suffering from a heart attack will wait one hour longer than a man from the onset of pain to arrival at a hospital, will get lower priority when waiting for an ambulance, and will wait twenty minutes longer to be seen at the hospital.

The reality that female bodies are simply not afforded the same level of medical attention as male bodies is often brushed aside with the riposte that, on average, women enjoy more years of life than men. But while it is true that female life expectancy remains a few years longer than male life expectancy (although that gap is narrowing as women’s lives have become less prescriptive and occupational safety in male-dominated jobs has become more stringent), there is evidence to suggest that the female mortality advantage isn’t exactly secure.

A 2013 paper that examined trends in US mortality rates from 1992 to 2006 in 3,140 counties reported that even as mortality decreased in most counties, female mortality increased in 42.8% of them. And while men’s years of good health have increased in line with their longevity, both women’s longevity and active years have increased at a much lower rate: thirty years of US health data showed that, while women live on average five years longer than men (in Europe it is 3.5 years), those years are spent in ill health and disability.

The result is that US women no longer have more active years than men, despite their longer lives, and while women account for 57% of US citizens aged over sixty-five, they make up 68% of those who need daily assistance. In 1982 both men and women who lived to eighty-five could expect two and half further years of active healthy life. For women, that figure hasn’t changed, but an eighty-five-year-old man alive now can expect to be active and healthy until he’s eighty-nine. The trend of increasing longevity and good health amongst men can also be found in Belgium and Japan. A WHO paper into women’s health in the EU reported that in 2013, “even in countries with some of the highest overall life expectancy in the Region, women spent almost 12 years of their life in ill health.” And, yes, it would be nice to have some sex-disaggregated data on why this is happening.

A particularly troubling side effect of Yentl syndrome is that when it comes to medical issues that mainly or only affect women, you can forget about including women in trials because here the research is often lacking altogether.

Premenstrual syndrome (PMS) is a collection of symptoms that can include among other things: mood swings, anxiety, breast tenderness, bloating, acne, headaches, stomach pain and sleep problems. PMS affects 90% of women, but is chronically under-studied: one research round-up found five times as many studies on erectile dysfunction than on PMS. And yet while a range of medication exists to treat erectile dysfunction there is very little available for women, to the extent that over 40% of women who have PMS don’t respond to treatments currently available. Sufferers are still sometimes treated with hysterectomies; in extreme cases, women have tried to kill themselves. But researchers are still being turned down for research grants on the basis that “PMS does not actually exist.” Period pain — dysmenorrhea — similarly affects up to 90% of women, and according to the American Academy of Family Physicians it affects the daily life of around one in five women. The level of pain women experience on a monthly basis has been described as “almost as bad as a heart attack.” But despite how common it is and how bad the pain can be, there is precious little that doctors can or will do for you. A rare 2007 grant application for research into primary dysmenorrhea described its causes as “poorly understood” and treatment options as “limited.” The prescription medications which are available have serious possible side effects and are by no means universally effective.

When I went to my (male) doctor about period pain that wakes me up at night and leaves me in a moaning fetal position in the daytime, he more or less laughed me out of the room. I haven’t bothered trying again. So imagine my joy when I read about a 2013 study that seemed to have found a cure. The “primary outcome” of a double-blind, randomized, controlled trial of sildenafil citrate, was, ladies, you may want to sit down for this: “total pain relief over 4 consecutive hours,” with “no observed adverse effects.” Imagine.

We have only one treatment for women with weak contractions, and it doesn’t work half the time. Compare this … to the around fifty drugs available for heart failure.

Created in 1989, sildenafil citrate is the medical name for Viagra. In the early 1990s, the drug was being tested as a heart-disease medication. It turned out not to be great at that, but one thing participants did report was an increase in erections (yes, all the trial participants were men). Total erectile dysfunction affects between 5 and 15% of men depending on age, with about 40% of men experiencing it to some degree — and so naturally the researchers were keen to explore this alternative use for their drug. By 1996, sildenafil citrate had been patented in the US and by March 1998 it was approved by the FDA. A happy ending for men, then.

But what if the trial had included women? The outcome of the 2013 study is suggestive. The trial had to be stopped because the funding ran out, meaning the researchers did not meet their sample size and therefore could not confirm the primary hypothesis. They called for “larger studies of longer duration, likely multi-center” to confirm their findings.

These studies have not happened. Dr Richard Legro, who led the study, told me he applied twice to the NIH for funding “to do a longer and larger study and also to compare sildenafil to the standard of care, a non-steroidal anti-inflammatory agent.” He was rejected both times. In each case, the grant “was deemed to be in the lower half of grants submitted.” It wasn’t even reviewed. Legro tells me that the comments he received “indicated that the reviewers did not see dysmenorrhea as a priority public health issue.” They also didn’t “fully understand clinical trial design of dysmenorrhea trials.” When I ask him if he thinks he will ever get funding, he says, “No. Men don’t care or understand dysmenorrhea. Give me an all-female review panel!”

The failure of pharmaceutical companies to step in here and capitalize on what is surely a gold-plated commercial opportunity may seem baffling, but it’s quite possibly just another data-gap problem. In an email, Legro told me that, for cost reasons, the pharma industry “doesn’t usually fund investigator-initiated projects,” particularly of drugs that are available generically. And this may be where the data gap comes in: there simply isn’t much research done on dysmenorrhea, which makes it difficult for pharma companies to know exactly how much money could be made on such a drug — and therefore makes it harder for them to decide to fund trials. Especially if the people making the decisions happen not to be women. Legro also suggested that pharma companies may not want to risk doing tests in women in case of negative findings that would endanger the use of sildenafil in men. In short, it seems that pharma companies may in fact not see this as a gold-plated commercial opportunity. And so women carry on being incapacitated by pain on a monthly basis.

Male-dominated funding panels may also explain why we have so few drugs available for uterine failure. Every day 830 women around the world die due to complications during pregnancy and childbirth (in some African countries more women die annually from childbirth than at the height of the Ebola epidemic). Over half of these deaths are explained as being a result of problems with contractions, often because the contractions are too weak for the woman to give birth. The only medical treatment available for women whose contractions aren’t strong enough is the hormone oxytocin, which works about 50% of the time. Those women go on to give birth vaginally. Women who don’t respond to oxytocin are given an emergency caesarean. In the UK weak contractions are the reason given for a majority of the 100,000 emergency caesareans carried out each year.

We currently have no way of knowing which women will respond to oxytocin, which clearly isn’t ideal: all women, including those for whom it will result in a pointless and harrowing delay, have to go through the process. This happened to a friend of mine in 2017. After being in hospital in excruciating pain for two days (on her own for much of it as her partner had been sent home), she was only 4 cm dilated. Eventually she was taken off for a C-section, and she and the baby were fine. But the experience left her traumatized. She had flashbacks for the first few weeks after she gave birth. When she talks about the internal exams and procedures, she describes it as a violent assault. It was, she says, brutal. But what if it didn’t have to be this way? What if theyd known from the beginning that she was going to need a caesarean?

In 2016 Susan Wray, a professor of cellular and molecular physiology at the University of Liverpool, gave a lecture to the Physiological Society. Wray is also the director of the Centre of Better Births in Liverpool Women’s Hospital and she explained that recent research revealed that women with contractions that were too weak to give birth had more acid in their myometrial blood (the blood in the part of the uterus that causes contractions). The higher the levels of acid were, the higher the likelihood a woman would end up needing a cesarean, because oxytocin isn’t, it turns out, that effective on women with an acidic blood pH.

But Wray didn’t simply want to be able to predict the need for a cesarean. She wanted to be able to avoid it. Together with her fellow researcher Eva Wiberg-Itzel, Wray conducted a randomized control trial on women with weak contractions. Half of them were given the usual oxytocin; half were given bicarbonate of soda (known in America as baking soda), and then given the usual oxytocin an hour later. The change was dramatic: 67% of women given just oxytocin went on to give birth vaginally, but this rose to 84% if they were given bicarbonate of soda an hour before. As Wray pointed out, the bicarb dose wasn’t tailored to body weight, it wasn’t tailored to the amount of acid in the blood, and the women weren’t given repeated doses. So the efficacy could turn out to be even higher.

This finding could not only be transformative for the tens of thousands of women a year who have what could turn out to be unnecessary surgery (not to mention saving the NHS a substantial amount of money). It could save women’s lives in countries where cesarean sections are risky or not readily available — not that you have to live in a low-income country for a C-section to be risky: you could just be a black woman living in the United States.

The US has the highest maternal mortality rate in the developed world, but the problem is particularly acute for African Americans. The World Health Organization has estimated that the death rate of black expectant and new mothers in the US matches that of women in much lower-income countries like Mexico and Uzbekistan. Black women in America have worse health outcomes overall than white women, but when it comes to pregnancy and childcare the comparisons score off the charts: African American women are 243% more likely than white women to die from pregnancy and childbirth-related issues. And it’s not just because African Americans tend to be poorer: a 2016 analysis of births in New York City found that “black college-educated mothers who gave birth in local hospitals were more likely to suffer severe complications of pregnancy or childbirth than white women who never graduated from high school.” Even global tennis superstar Serena Williams is not immune: in February 2018 she revealed that she had almost died following an emergency C-section. African American women also have higher rates of cesarean section and a 2015 study from Connecticut found that — even when controlling for socio-economic status — black women were more than twice as likely to have to return to hospital in the month following surgery. So Wray’s research could be transformative here.

But it looks like we aren’t going to see the fruits of her labor any time soon. When Wray discovered that the British Medical Research Council was offering funding for research that would benefit low- and middle-income countries, she decided to apply. And yet, despite all the data about how dangerous weak contractions can be, she was turned down. The research was “not a high enough priority.” So currently we have only one treatment for women with weak contractions, and it doesn’t work half the time. Compare this, Wray says, to the around fifty drugs available for heart failure.

The evidence that women are being let down by the medical establishment is overwhelming. The bodies, symptoms and diseases that affect half the world’s population are being dismissed, disbelieved and ignored. And it’s all a result of the data gap combined with the still prevalent belief, in the face of all the evidence that we do have, that men are the default humans. They are not. They are, to state the obvious, just men. And data collected on them does not, cannot, and should not, apply to women. We need a revolution in the research and the practice of medicine, and we need it yesterday. We need to train doctors to listen to women, and to recognize that their inability to diagnose a woman may not be because she is lying or being hysterical: the problem may be the gender data gaps in their knowledge. It’s time to stop dismissing women, and start saving them.

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The above is an excerpt from INVISIBLE WOMEN by Caroline Criado Perez. Copyright © 2019 by Caroline Criado Perez. Used by permission of Abrams Press, an imprint of Harry N. Abrams, Inc., New York. All rights reserved.

Caroline Criado Perez is a writer, broadcaster, and feminist activist, named Liberty Human Rights Campaigner of the Year and OBE by the Queen. She has a degree in English language and literature from the University of Oxford, and she studied behavioral and feminist economics at the London School of Economics. She lives in London.