The Gender Data Gap in Medicine & Healthcare

The Gender Data Gap in Medicine & Healthcare

“For millennia, medicine has functioned on the assumption that male bodies can represent humanity as a whole,” says Criado Perez. “As a result, we have a huge historical data gap when it comes to female bodies. Women are dying, and the medical world is complicit. It needs to wake up.”

I recently finished the book, Invisible Women: exposing data bias in a world designed for men by Caroline Criado Perez. I was absolutely blown away after every page I read, and am deeply concerned about how much I, even as a female myself, overlook the ways that society is ultimately created for men and by men, thus disadvantaging women at every level.

Each chapter educated and inspired me, but the Going to the Doctor section particularly concerned me considering I am going into the field of healthcare. In this blog post I have summarised a few of the most outstanding points along with statistics and study findings (hover over for the source) about how women are disadvantaged in medicine, right from clinical trials to the consulting room.

I highly recommend reading Invisible Women; it is no doubt one of my favourite non-fiction books. It is written with such passion and clarity which left me feeling angry at society but equally equipped to call it out and fight for change. Criado Perez also makes a great deal of effort to examine the situation across all levels of development (stressing that this issue transcends across borders) and points out how women of ethnic minorities (and also non-heterosexual) have most things even worse. It’s one thing being a woman in a patriarchal society, but it’s another being a women of colour in a white supremacist patriarchal society.

No data to work from: medical research

Considering the female population represents half of the population, you’d expect that trials designed to test the safety and efficacy of new drugs or treatments would test on both men and women. You’d be wrong. This under-representation of females in clinical research leads to treatments being approved, when actually how safe and effective they are in female bodies hasn’t fully been tested, leading to more adverse outcomes in women. For example, most early research in cardiovascular disease was conducted on men and even today only 25% of participants across 31 landmark studies for congestive heart failure conducted between 1987 and 2012 were female. Women make up only 32% of participants in studies on coronary stents, despite women having worse outcomes than men. Maybe one reason why women have worse outcomes is because they aren’t actually being researched on.

Are these the reasons why women in Britain are 50% more likely to be misdiagnosed following a heart attack?

Why aren’t women included in medical research?

Women are largely excluded from medical research, because of the lame excuse that female bodies are too complex, too variable and too costly to be tested on. Including the 50% of the population into research cohorts is seen as a burden. Another reason for the lack of female representation in trials is because it’s claimed to be harder to recruit females, which is true when you consider that women do the majority of the unpaid care work in society. But as Criado Perez says, ‘this is an argument for adapting trial schedules to women, rather than simply excluding them’.

And some researchers don’t even attempt to make an excuse, and say that gender representation is just fine (despite an overwhelming mass of evidence proving that there are significant sex differences that need to be addressed in research). A 2018 paper published in the Journal of Pharmacology entitled ‘Gender differences in clinical registration trials: is there a real problem’ concluded that no, the problem was not real (the book goes into great depth why this study is hugely unreliable, and funnily enough all the authors were male).

‘too hormonal’

A common excuse for not testing on women is that the female body is too hormonal, too complicated, too abnormal, too not like a man’s. But the problem is that around half of the people who will be having this condition and requiring treatment and taking the drug/having the surgery in question are going to be hormonal and complicated and not a man. Yet when women are included in trials (yipee), they tend to be tested in the early follicular phase of their menstrual cycle, when hormones are at their lowest (to minimise the possible impacts oestradiol and progesterone may have on the study outcomes) i.e. when they are most like a man! ‘But real life isn’t a study and in real life those pesky hormones will be having an impact on outcomes’. We know that the menstrual cycle impacts the treatment response with antipsychotics, antihistamines, antibiotics, antidepressants and heart medication, essentially meaning at some stages of the menstrual cycle a dose could be too high and at some too low leading to the wrong effect, and so sometimes death.


It’s important for researchers to include enough female participants in their studies, but it’s also just as important to sex-disaggregate their data when analysing their results. If you lump all the data from how the men and women did in a study and decided whether the treatment is effective/safe enough, you could be missing whether it was effective at all in just one sex alone. Most researchers nowadays aim to include an equal split between male and females in their study cohorts but then fail to actually analyse how their research affected the men and women differently, with an FDA audit finding that a third of documents did not sex-disaggregate their outcomes, and 40% didn’t even specify the sex of their participants!

Another problem is that many of the early stages of trials that are conducted on cells, the majority of the cells are derived from males (a 2011 review of ten cardiovascular journals found that when sex was specified, 69% of cell studies reported only using males). There should be representation of both sexes right from phase 1 trials, as important findings could be missed. This raises the scary question of ‘how many treatments have women missed out on because they had no effect on the male cells on which they were exclusively tested?’.


The exclusion of female bodies in medical research stems from treating the male body as the default, universal human body. Yet we know there are sex differences in every tissue and organ system in the body , as well as in the ‘prevalence, course and severity’ of the majority of common human diseases.

Importantly, sex differences even appear ‘in the expression of a gene found to be important for drug metabolism’, and women develop higher antibody responses to vaccines, and so have more frequent and severe adverse reactions. A 2014 paper proposed developing male and female versions of influenza vaccines because of this – so why haven’t we? Women are more likely than men to experience an ADR (adverse drug reaction), with more than 2 million recorded in women compared to 1.3 million in men.

I’m struggling to write this post without re-writing the whole book, so I urge you to buy it – you will not regret it. I was going to touch on how this gender data bias has roots even still in the medical school curriculum and textbooks, as well as how women are treated differently as patients in terms of empathising their pain, but there is so much information that I think I will spread it over a few blog posts!

Hopefully this blog post has given you a little insight into what I’ve learnt about the gender data gap within medical research, and how this is causing women to not receive the treatment they deserve and so are unnecessarily dying. Look out for upcoming blog posts about how other areas of medicine and healthcare are disadvantaging women.

To buy the book on Amazon:

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The Conscious Medic

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