Exclusion of women from clinical trials is rooted in historical tragedy. In the 1950s, nearly 20,000 Americans took part in clinical trials for the drug thalidomide, including 600 pregnant women hoping to ease morning sickness. But the drug caused serious birth defects, including missing or deformed limbs.
The resulting outcry helped prompt a 1977 Food and Drug Administration recommendation to exclude women of childbearing age from early-stage trials, stalling a push at the time to bring more women into scientific research.
However, scientists found that excluding women from early drug tests came with its own set of consequences, including limiting understanding of how women respond to various medications. So, in 1986 the National Institutes of Health took the first in a series of steps to bring women back in.
Today, trial participation among women has increased, but they are often still underrepresented.
A 2022 study found that women only made up, on average, 41% of participants in more than a thousand reviewed trials — numbers that were often lower than the percentage of women affected by the diseases studied. In psychiatry, for example, women comprise 60% of patients but only 42% of trial participants.
“Historically, conditions that primarily affect women have just not been researched at the same rate as indications that affect men,” said Cara Brant, CEO of Clinical Trial Media, a global recruitment and retention company. “And this is throughout the healthcare industry, both government and private.”
Recently, progress is being made in research for diseases that primarily affect women, including breast cancer and endometriosis, Brant said. In March, President Joe Biden announced a new initiative to expand and improve women’s health research, which adds to ongoing efforts to diversify trial participation.
“It's starting to feel like there's momentum around women's health research,” Brant said.
Encouraging participation
Enrolling women in clinical trials is crucial because women often react differently to drugs and have different presentations for many diseases, including cancer and cardiovascular diseases.
“Our bodies are different. We process and metabolize medication differently,” Brant said. “Understanding that, I think, will help to improve drug effectiveness, safety and tolerability.”
Women are also disproportionately affected by diseases such as Alzheimer’s disease and autoimmune disorders, and need better options for female-specific problems, such as menopause symptoms.
Women appear willing to sign up for trials. COVID-19 helped raise awareness about the role and availability of clinical trials, Brant said.
“It opened everybody's eyes to this industry that helps bring medications to market faster, and creates opportunities to see specialists and to get expert medical care in under-researched areas,” she said. “Interest is through the roof right now and I think women are just as interested as men, if not more.”
Although they may be eager to sign on, logistical barriers can block their path. Often they are the primary caregivers for children or aging parents in addition to work and may struggle to balance those responsibilities with that of a clinical trial commitment.
“It’s almost impossible for moms to find time for themselves, much less the time that’s needed to participate in a clinical trial,” Brant said. “One thing that we hear consistently from women is that they have challenges with childcare and coming to appointments and just finding time for a scheduled visit.”
Sites looking to increase women’s participation need to make changes to encourage participation, she said.
For one, they need to increase appointment flexibility, she said. Adjusting site hours to include later appointment times or weekend visits makes it easier for women to make the schedule work.
“We have to look at how to be flexible and adapt to their lifestyle and their needs,” Brant said, pointing out that remote visit options offer another convenient option. “Maybe there's a telehealth visit or they can have their labs done [locally] as opposed to attending the site — it takes a lot of thoughtfulness and creativity, but I think that's what's needed at this moment.”
Trials should also make space for children, so women who can’t find childcare don’t have to cancel appointments or drop out.
“I do think that when sites create a friendly environment for a woman who may have to attend an appointment with her child, it’s going to go a long way.” Brant said. This can be as simple as offering puzzles and games to keep children entertained in the waiting room. “Women love to know that their children are being thought of. That's a reflection on them and it makes them feel more relaxed, more comfortable. They don't have to feel on edge about bringing their child.”
Sites also need to open the lines of communication to get better results, Brant said..
“What we hear frequently from any participant is that for people [who] are new to clinical research there’s a lot of anxiety around what to expect: Where am I going? What happens at the study visit? How many visits are there? How long is it going to be?” Brant said.
Providing guidance and information can ease uncertainty and make women more willing to participate. Asking participants for regular feedback to identify improvement targets can also help. For example, a survey might reveal that parking at the site is challenging, adding 20 to 30 minutes to the visit.
“This person, who was showing up for a visit on time, is now going to be late to work,” she said. “That's a problem. It's such a small thing, but it's real.”
Because trial participation can be taxing, sites should also let women know they appreciate the effort, acknowledging the sacrifice participants make. This might include a handwritten thank-you card or a small, inexpensive token of appreciation that shows you're thinking about them, Brant said.
“I think women, like everybody, want to be heard, so give them an opportunity to have a voice and be included in the clinical trial process,” Brant said.