Today, women are a vital part of clinical trials, significantly improving women’s health care. Inclusion is only part of the job. A larger and more diverse group of women is needed to ensure that we learn how interventions work in all women to best inform clinical practice.
What Is a Clinical Trial?
There are two types of clinical studies: clinical trials and observational studies. In clinical trials, some or all participants receive a specific intervention for the prevention or treatment of a medical condition. The intervention is what the trial is testing and could be a product like medication or vaccine but might be an exercise regimen or something else. During an observational study, participants are not given any interventions. Instead, researchers observe their lifestyle and medical choices to see how these things affect their health. It’s common for people to use the terms clinical studies and clinical trials interchangeably. Studies that involve medication may also be called drug trials, and studies that involve vaccines may be called vaccine studies.
Depending on the particular trial or observational study, the goal may be to determine:
- How to prevent people from developing a particular medical condition
- If a medication or other treatment is:
- Effective in treating a specific medical condition
- More effective than another medication or treatment
- Safe to use
- Ways to improve quality of life for people with a specific medical condition
- What makes people more or less likely to develop certain health conditions
Why Representation Matters
Because of hormones, genetics and social factors, women and men often have different health needs. They may not respond to an intervention in the same way. Men and women may benefit from differences in vaccine or medication doses, schedules, treatment plans or support services. Women also have unique health care concerns. For these reasons, it’s essential to include women in clinical research.
Here are just a few examples of how differences between men and women may impact their health and treatment needs:
- Among smokers, women are more likely to develop lung cancer than men, even if they smoke the same number of cigarettes.
- Because women are often the primary caretaker for children, childcare issues are more likely to affect their health or their ability to stick with a treatment plan.
- Heart attack symptoms are different in women than in men.
- Women receiving substance use treatment are two to three times more likely to have post-traumatic stress disorder (PTSD) than men.
To fully understand women’s health needs, women need to be included in clinical research.
A Brief History of Women and Clinical Trials
The 1970s and Before
Starting in 1977, the US Food and Drug Administration (FDA) officially banned most women of “childbearing potential” from participating in clinical studies. The intention was to prevent congenital disabilities due to unknown side effects in drug trials.
Earlier researchers also excluded women from clinical studies because they thought hormone changes during the menstrual cycle would make study results less reliable. This thinking extended beyond human participants. Many scientists doing animal research excluded female animals for the same reason.
Researchers felt that by using only men and male animals, there would be less variation in study results. They also assumed that study results would apply to women in the same way as they applied to men.
The 1980s and 1990s
By the early 1980s, researchers better understood how factors such as age and body size influence the safety and effectiveness of medications or other medical treatments. Some began questioning whether the results of earlier all-male clinical trials applied to women.
In 1985, a new report encouraged researchers to reconsider the role of clinical trials in women’s health. This report led to new guidelines from the FDA and the National Institutes of Health (NIH) that encouraged including more women in clinical studies. However, actual changes were very slow.
In 1993, the FDA officially condemned the 1977 policy. The same year, Congress passed a law requiring women to be included in NIH-funded clinical trials. This law also mandated better representation of people of color in clinical studies.
The Early 2000s
Since the early 2000s, the number of women participating in clinical studies has increased significantly. However, there is still a lot of room for improvement. Women remain underrepresented in some areas of medical research. They’re also more likely to face barriers to participation, such as juggling complex home and work responsibilities.
Currently, all clinical studies that receive NIH funding need to include men and women or give a reason for why one group is excluded. Since 2016, the NIH has also required that sex be included as a study variable for humans and other animals. Many research teams are taking steps to eliminate barriers to participation, but this continues to be a challenge for many women who want to participate in clinical trials.
Evolving Understanding of Sex and Gender in Clinical Trials
While the words sex and gender are often used interchangeably in daily life, they don’t mean the same thing from a scientific perspective. In this instance, sex refers to someone’s biological and genetic components, while gender refers to a person’s behavior and identity. Over the past couple of decades, researchers have learned more about the different effects of sex and gender on health. Because of this, many researchers are beginning to look at sex and gender as separate variables in clinical trials, along with other factors like age, income level or race.
What Can Be Done to Include More Women in Clinical Trials?
Research teams and individual women can do several things to increase female participation in clinical research and trials.
Research teams can:
- Advertise trials in places women are likely to see them.
- Consider how factors like childcare may impact female participation in the study and consider being flexible with the timing of study visits.
- Include more women on the research team.
- Solicit feedback from female participants after the trial to learn about potential improvements.
- Work with a diverse participant advisory board to get feedback on all parts of the trial.
Women can also help increase representation in clinical research and trials by:
- Getting involved with a participant advisory board.
- Participating in a clinical trial.
- Pursuing careers in medicine, research and science.
- Teaching other women about clinical trials and how to become involved.
Participating in a Clinical Trial
Both healthy women and women with chronic or serious medical conditions are needed to participate in clinical trials. Talking with your medical provider is a great place to start. They can help you learn about current studies that might be a good fit for you.
Medically reviewed by Kathleen Neuzil, MD, MPH, FIDSA.
