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Why are women and people with cycles underrepresented in health research?

The consequences have been dangerous.

The exclusion of women and people with cycles from research studies has led to a dearth of information about their health. This exclusion has been a result of historical, cultural, and systemic forces that stigmatize women’s participation in scientific processes.

Luckily, things are changing. In the past few decades, there has been a momentous shift in attitudes and requirements for who should be included in clinical studies, positively influencing research for the benefit of women, people with cycles, and other historically marginalized groups. 


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Why have women and people with cycles been excluded in health research?

In the first half of the 20th century, there was limited regulation in research. From the 1940s to the 1970s, the drugs thalidomide and diethylstilbestrol were prescribed to women for various ailments, although the negative effects of these medications on the babies of pregnant women had not been explored before their approval for public use (1,2). Tragically, thousands of women who took thalidomide while pregnant gave birth to babies with severe limb deformities (3). In response, countries worldwide began more strictly regulating the way medications are studied, approved, prescribed, and marketed, in order to better protect the public. In the U.S., part of these standards included excluding all women of reproductive age from most early-stage drug research (4). In the subsequent decades, clinical trials were frequently based on data collected predominantly from white men (5).

Since women weren’t represented in important medical research, the quality of healthcare that was available to them was compromised (6). There were some exceptions, including studies on the efficacy of hormonal birth control in the 1970s and the 1980s, some of which were led by female scientists (7). However, research on health issues that affect all sexes, like hypertension and diabetes, predominantly used men as subjects. As a result, men became perceived as the “gold standard” of research subjects, by scientists (8), with the false belief that women’s bodies would always behave similarly to men’s bodies in clinical trials (5). Additionally, some scientists believed women’s bodies were too complex and too expensive to study (5). Including women in research would mean that scientists would have to account for factors like the menstrual cycle and the possibility of pregnancy. Instead, scientists of the period chose to ignore these key differences.

Public concern over a lack of data on how drugs affect women and the belief that women should be able to choose whether to participate in research spurred growing activism on behalf of inclusive research. In the U.S., the Women’s Health Movement encouraged women to advocate for their health and eventually influenced the development of a federal Task Force on Women’s Health Issues, in 1983, which recommended that more research be done in the area of women’s health (9). And in 1993, the National Institutes of Health mandated that any clinical research study that received federal funding include women and minorities (10). In Canada, rising concerns about a deficit of research on breast cancer and gynecological cancers led to the development of the “Canadian Guidance Document on the Inclusion of Women in Clinical Trials (11),” which recommends the inclusion of women in all stages of research, so that scientists can understand the impact of new drugs on specific sexes (11).

In the U.S., by the early 2010s, women accounted for 45% of subjects in middle- and late-stage trials of new drugs (12). However, female inclusion still varies widely, depending on the field of research. Women still remain underrepresented in research of heart disease and cancer, diseases that are the leading causes of death for women (13). And, a study in 2019 found that women, and especially women who are pregnant and elderly, continue to be underrepresented in clinical trials (11). Importantly, even when women are included, clinical trials still frequently fail to analyze and report on sex-specific differences, limiting our ability to understand how sex can influence health and disease (14).

Why is it important to include women and people with cycles in research? 

Because women and people with cycles have been underrepresented in health research, we now know far less about how diseases affect women and people with cycles, in comparison to men, which can lead to dangerous consequences.

Though heart disease is the leading cause of death among men and women, a majority of research about heart disease has been conducted on men (5,15). As a result, past research has missed out on key differences between sexes, when it comes to heart disease. Women, for instance, have more incidents of heart disease than previously thought, and they die from heart disease more frequently than men (15,16). Research has also missed key differences in how heart attacks present in women: while both men and women experience chest pain, women are more likely to report pain radiating to the back, neck, or jaw, as well as left arm pain (17). Failing to understand symptoms of heart attack in women and people with cycles puts them at risk of being misdiagnosed or treated incorrectly.

Gender and sex biases in research have also affected drug research and development. For decades, healthcare guidelines and standards did not differentiate between sexes and did not address how drugs affected women (6), though women have distinct physiological and anatomical distinctions from men, like differences in body mass, organ function, and hormone levels (18). A man and a woman can be prescribed the same dose of a drug, but differences in body composition and body function may lead to different effects in different bodies (18). 

Gender and sex disparities in research also lead to a lack of resources and information about women’s health. Inadequate health literacy is linked to poor health outcomes and higher mortality (19).  Sexual and reproductive health education is a necessary component to improve the lives of women and people with cycles. For instance, we know that reproductive health literacy leads to the reduction of STIs, unintended pregnancies, and maternal mortality (20). 

Toward a more inclusive future

Research that is inclusive of women and people with cycles has come a long way since the 20th century. In recent years, there has been an uptick in advocacy and research in regards to women and people with cycles. Historic organizations like the Women’s Health Initiative and the National Women’s Health Network continue to fight for the right for women and people with cycles to have access to menstrual products, birth control, health screenings, and health information.

Tracking your cycle with Clue also contributes to advancing health research for women and people with cycles. Clue works with top research institutions that use de-identified Clue data  (all personally-indentifiable information is always removed first) to answer questions like: How does contraception impact sex drive or breast tenderness patterns? Does air pollution influence cycle length variability? Do sexually transmitted infections impact PMS symptoms?

Inclusive research leads to better health outcomes for women and people with cycles, allowing everyone to live their life to the fullest.

Clue strives to continue to support the health of women and people with cycles through providing free and easily accessible services to all. We strive to de-stigmatize issues surrounding periods, birth control, and fertility. Signing up for Clue means the power of taking control of your body is in your hands. Donating to Clue’s research initiatives can ensure there is adequate funding for research and projects that benefit all women and people with cycles. 

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