Research is the backbone of everything we do at Modern Fertility. Without clinical research, we would know ~very~ little about how our bodies function and what hormones play the biggest role in fertility (and, as you might already know, hormones are kind of our thing).
Because research is so core to Modern Fertility, when we see gaps in information about fertility, we do our best to fill them. Along with the development of new fertility products, we also publish research in the form of our Modern State of Fertility surveys and IRB-approved studies based on data we collect from customers who opt in.
Historically, research looking into the health of people with ovaries in general has been underfunded — and up until very recently (we’re talking the past decade), many aspects of our fertility were pretty unknown. That’s why, in this article, we’re reviewing some of the biggest gaps in health research, unpacking why they exist, and sharing how we hope to change things for the better.
But first… a note on sex, gender, and the language we use
The National Institutes of Health (NIH), the agency behind government-funded clinical research in the US, asks researchers to report the breakdown of participants based on “sex/gender.” Here’s how they define the difference:
- Sex: “Biological differences between females and males, including chromosomes, sex organs, and endogenous hormonal profiles.”
- Gender: “Socially constructed and enacted roles and behaviors which occur in a historical and cultural context and vary across societies and over time.”
But within the “sex/gender” category of reporting, there are only two options: “female” and “male.” The thing is, as NIH themselves explained, “sex” and “gender” are not the same thing — not all women are the same “sex,” and not all people with "female" sex characteristics identify as women. Beyond that, there are no options to report participation of non-binary, transgender, or intersex individuals.
Since this is the language we’re presented with when looking at the history of health research (and the only data we can go off of), we’ll be using “sex” terms (i.e., “female,” “male”) when talking about areas of research where biological factors play a role. (Here’s to hoping new, more inclusive language emerges in the near future.)
The biggest research gaps we’ve found
There are research gaps across many different areas of female health, so we’ve broken them down into three different sections for easy scrolling: overall health, reproductive health, and sexual health.
Heads up: Some of the research we're citing is a few years old. Unfortunately, comprehensive studies evaluating these gaps (much like research into those areas in general) aren’t frequently conducted. We did our best — as in truly scoured the internet — to find the most up-to-date evidence from reputable sources.
In 2014, Brigham and Women’s Hospital in Boston released an in-depth report on where more sex-specific medical research was needed. Out of the areas they identified, recent research shows these gaps continue to exist years later:
- Cardiovascular disease: Cardiovascular disease is the leading cause of death for Black and white females in the US. Yet the American Heart Association (AHA) reported in 2020 that only 38.2% of clinical trials included females between 2010 and 2017 — and the NIH reported that in 2018, only 9% of participants were Black. (AHA hasn’t published a more recent review of clinical trials, and the NIH most recently reported on demographic breakdown of trial participants in 2018.)
- Depression: Females are twice as likely to have depression than males are… yet, historically, the vast majority of research has been conducted on males (both animals and humans). A 2019 article explains that things haven’t gotten much better in contemporary times.
- Alzheimer’s: Two-thirds of the 5.7 million+ people with Alzheimer’s disease are females. While this is in part due to the fact that females tend to live longer than males, there has been very little research looking into the different biological markers, genetic variations, or lifestyle factors influencing the risk of Alzheimer’s within the two populations (including menopause).
Below, we’re covering the largest gaps we’ve found in the research around reproductive health. But because not all research gaps are easily quantifiable (they’re gaps, after all), there are very possibly areas we’ve missed:
Our healthcare system is very reactive — meaning it’s focused on developing treatments for conditions instead of preventing them altogether. How does this play out in fertility research? The NIH dedicates funding to infertility but not fertility. In fact, NIH estimates spending only $158 million on infertility research in 2020. While that number might sound like a lot on its own, over 3x the amount ($515 million) is estimated for pregnancy research.
A few other head-scratchers: In the last 20 years, there have been 5.5x more studies about male infertility than female infertility (per a comparison of this search and this search on PubMed). And in 2019 alone, there were 1,025 studies published about erectile dysfunction (!) as compared to 176 studies exclusively about female infertility.
The bulk of research ends up being conducted by fertility clinics — where a good portion of patients may be experiencing infertility (though it’s important to remember that about half of infertility issues stem from male factors).
Birth control and mental health
Very little research has been conducted looking into the impact of contraceptive use on mental health, and vice versa — even though mood changes are often reported as side effects of hormonal birth control. In Brigham and Women’s Hospital’s 2014 report, they also identified a gap in how oral contraceptives and antidepressants interact and affect one another.
Pregnancy and medication
According to the American College of Obstetricians and Gynecologists (ACOG), even though more than 60% of pregnant people use prescription drugs during their pregnancies, most of the these medications haven’t actually been tested during pregnancy — in large part because of the fear that these medications might harm the unborn fetus. Still, ACOG recommends pregnant people be seen as scientifically complex instead of vulnerable and encourages their involvement in clinical trials if they consent (and so does the FDA).
Endometriosis is a painful condition where tissue similar to the lining of the uterus grows outside of the uterus. 1 out of every 10 people with female reproductive systems has endometriosis.
On average, it takes 10 years from the onset of symptoms to get an accurate diagnosis of endometriosis in the US. Why such a long time? The Endometriosis Foundation of America believes it’s due to a general lack of knowledge among the medical community — not to mention the fact that endometriosis research is extremely underfunded. (People with endometriosis also have higher rates of fibromyalgia, another chronic-pain condition.)
On July 31, 2020, Congress approved an amendment to double the year’s funding for endometriosis research — a move made possible by Iowa Congresswoman Abby Finkenauer, who has lived with endometriosis since she was a teenager.
Polycystic ovary syndrome (PCOS)
Polycystic ovary syndrome, or PCOS, is a hormonal imbalance characterized by cyst-like growths on the ovaries and irregular cycles that affects 1 in 10 people with ovaries.
In a 2019 report, the NIH identified a gap in clinical research investigating why certain comorbidities (multiple conditions commonly occurring at the same time) are often connected to PCOS. PCOS increases the risk for type 2 diabetes, cardiovascular disease, uterine cancer, and mental health disorders like anxiety and depression… but, as NIH discovered, we don’t entirely know why.
As common as PCOS is, it’s underdiagnosed. This could be a result of inconsistent diagnostic criteria across healthcare providers (though the Rotterdam criteria is the internationally recognized choice).
Uterine fibroids are non-cancerous tumors on the inside, outside, and muscle of the uterus that impact up to 80% of people with uteruses by the age of 50. Black people are more likely to get fibroids than people from other racial groups — and those fibroids may come at a younger age, be larger, and have more symptoms.
More research is needed to develop better, less invasive medical treatments to improve the lives of people with uterine fibroids. Right now, there are many options for treatment, but most either only address some symptoms, are very invasive, or involve newer technology that needs further testing.
While uterine fibroids disproportionately impact Black females, most published reports focus on white females. That said, in 2015, the National Institute of Environmental Health Sciences, a division of NIH, recruited 1,696 Black females to study uterine fibroid risk factors. (The results haven’t been published yet.)
The NIH estimates $17 million in funding for uterine fibroids in 2020. However, in August 2020, Senator Kamala Harris introduced a bill to expand uterine fibroid research by $30 million each year from 2021-2025 — as well as create a public education program and improve data collection among the most affected populations.
Around 35% of people in the US with vulvodynia have to wait 36+ months — and go to 15 medical appointments — after the onset of symptoms to get a diagnosis. Only half the people experiencing symptoms actually seek medical help, and of those who do, <2% get a diagnosis. Researchers aren’t totally sure of the reason for this, or why some people even get vulvodynia — but the fact that vulvodynia has consistently been one of the conditions with the least NIH funding likely plays a big role. A recent PubMed search shows only 731 published studies on vulvodynia, in contrast to 879 published studies on chronic pelvic-pain syndrome (CPPS) in males (PubMed search).
Vulvodynia can also cause vaginismus: painful contracting or spasming of the vaginal muscles while having penetrative sex, inserting a tampon, or getting a Pap smear. According to the Cleveland Clinic, the exact percentage of how many people vaginismus impacts is unclear because of stigma around openly discussing the issue with doctors. Only 383 studies have ever been published on vaginismus (based on a recent PubMed search).
Finally, the two major gaps we've found in sexual health research:
Since female orgasms aren’t directly linked to procreation in the same way male orgasms are, there hasn’t been much research devoted to them. But some argue that sexual pleasure should be a matter of public health. As of right now, the NIH doesn’t fund research explicitly looking into sexual pleasure — but we can’t be sure of exactly the reason why (though we can certainly guess!).
Sexual dysfunction refers to problems at any point in the sexual response cycle (excitement, plateau, orgasm, resolution) that result in decreased satisfaction during sexual activities.
Cleveland Clinic reports that 43% of females and 31% of males experience some degree of sexual dysfunction. Even so, as of the writing of this article, the number of studies published on “erectile dysfunction” are almost 3x the number published on sexual disorders common in females (per a recent comparison of PubMed searches, here and here).
In terms of treatment? Viagra, a popular medication that helps with erections, was approved by the FDA in 1998 — but the first sexual dysfunction medication for females, Addyi, wasn’t approved until 2015.
Why do these gaps exist?
There are a few different factors that have had a huge influence on whose bodies have been the most represented in clinical research and what has been focused on thus far.
Females (humans and mice) were excluded from research for decades
From 1977-1993, the FDA completely banned females of reproductive age from drug trials — and before 1993, inclusion of females in drug and clinical trials was encouraged, but it wasn’t required. The reason for this was three-fold:
- Researchers assumed that male and female bodies were essentially the same.
- Researchers worried that the fluctuations of hormones during the menstrual cycle would throw off their results.
- Researchers feared that experimenting on reproductive-aged females would hurt their fertility. (The assumption, of course, being that all people with ovaries automatically want to have kids.)
Then, in 1993 (a banner year for health research!), the FDA withdrew their restrictions and the NIH was mandated by law to require inclusion of people with ovaries and minority groups — moves largely influenced by the Congressional Caucus for Women's Issues (an organization within the House of Representatives). Even with these developments, researchers sometimes don’t include enough females or fail to identify the sex and race of their participants.
In 2016, the NIH required that scientists must also report on how sex may have an impact in both human and vertebrate animal studies in order to receive funding. Why animal studies, too? For a long time, the primary animals used in preclinical research were male rodents — researchers believed that female rodents’ estrous cycles (aka mice’s version of the menstrual cycle) made interpreting the results too complicated, just like in the case of humans.
What this tells us is that researchers were aware that our bodies function differently… but instead of letting that *inform* their research and lead to helpful discoveries, many just excluded them entirely. 2016 changed that.
25+ years later, we’re still playing catch-up
While females now make up about half of the participants in NIH clinical trials and 72% of FDA clinical trials across the board, the gaps we mentioned above still exist in individual research areas. The gaps are even bigger when you consider Black and LGBTQ+ people with ovaries.
NIH reports on “sex/gender” and “race” of their clinical trials separate from one another, so it’s tricky to figure out the *exact* number of Black females who participate in clinical research across different types of studies. But if you look at individual studies in terms of Black female participation, the numbers are very low. Here’s one example: Cervical cancer mortality rates are higher for Black females than they are for any other races, but Black females only made up 5% of participants in 2018 clinical trials.
One possible reason for the underrepresentation of Black individuals in clinical research, according to Dr. Ada Stewart, MD, FAAFP, the president-elect of the American Academy of Family Physicians, is a lack of trust in the medical community after a history of medical experimentation without consent.
What about LGBTQ+ representation in clinical trials? While the NIH doesn’t report on the sexuality of research participants, one 2014 analysis of NIH funding for LGBTQ+ health found there were 628 studies conducted by that year. Of those 628 studies (excluding ones around HIV/AIDS and sexual health), only 13.5% of the studies looked at LGBTQ+ females and only 6.8% looked at transgender individuals. That said, in 2015, the NIH launched the Sexual & Gender Minority Research Office, which has a dedicated focus on LGBTQ+ individuals. Still, according to the office’s 2018 report, “men who have sex with men” accounted for over half (56.5%) of the population studied that year.
Female pain is often not believed
In 2020, researchers drew parallels between present-day experiences of endometriosis and the old-timey theory of “hysteria,” explaining that people with endometriosis often report doctors telling them the pain is all in their heads. (It’s worth noting here that, technically, any pain we experience is “in our heads.”)
Never heard of “hysteria” before? Here’s a little history lesson: In ancient Greece, “hysteria” (derived from the Greek word “hystera,” meaning uterus) referred to the idea that the uterus would wander from its spot in the body and lead to physical symptoms. The believed cause? Not having kids. Through the next couple of centuries, hysteria evolved into a catchall condition marked by unexplained physical symptoms. What was initially known as hysteria is now referred to as conversion disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). When people with uteruses who experience chronic pain aren’t believed, it’s easy to connect the dots back to hysteria.
Another moment in history reaffirms this belief — especially how it has impacted Black people with uteruses. In the 19th century, Dr. Marion Sims, who is considered the “father of modern gynecology,” experimented on enslaved Black people without anesthesia to find a surgical treatment for vaginal fistulas (an opening that connects the vagina to another organ, like the bladder, colon, or rectum) and design the speculum (which is used today for vaginal exams of all kinds). Reflecting on this dark period in history, some suggest that a disbelief in Black people’s ability to feel pain was the rationale used for this and other examples of non-consensual medical experimentation.
Today, explains Dr. Nataki Douglas, MD, PhD, the Chief of the Modern Fertility Advisory Board, “Women of all races who experience pelvic and menstrual pain (due to conditions like endometriosis or uterine fibroids) are often told that it’s simply a natural part of being a woman. However, a 2012 meta-analysis of pain management and racial bias found that Black patients who reported pain were 22% less likely to get medication to treat it.”
To add insult to injury, as recently as 2017, 70% of people with chronic-pain conditions (like endometriosis or fibromyalgia) were female… yet 80% of pain studies used male mice or humans.
Female anatomy is often considered “taboo”
An underlying current beneath many of these research gaps is stigma surrounding the female anatomy. Even in modern times, sex ed’s focus on educating around abstinence and “the facts of life” ends up excluding some of our body parts entirely — namely, the vulva and clitoris. (Not-so-fun fact: The full anatomy of the clitoris wasn’t discovered until 1998.)
The weirdness around female anatomy can be traced through history. Remember “hysteria”? Well, Sigmund Freud, known as the “father of psychoanalysis,” had his own theory for what caused the condition: unfulfilled sexual desire. Freud is famous for having a *lot* of opinions about sexual desire, but one interesting one is his perspective on vaginal versus clitoral orgasms. He believed that clitoral orgasms were “infantile,” and that vaginal orgasms were “mature.” If someone couldn’t have a vaginal orgasm, they were seen as “frigid.”
Then there’s menstruation. For about as far back as you can find the written word, periods have been perceived as toxic or impure. There’s even a theory that the origin of the word “taboo” is a Polynesian word, “tapau,” which has been translated into both “sacred” and “menstruation.”
What does all of this have to do with gaps in research? The mystery of female anatomy and myths about how it works and what it does have very likely contributed to the areas of research that have been under-investigated. Like we mentioned earlier, researchers were so confused by female hormones that they avoided them entirely. Another possible example: Our historic lack of awareness around the clitoris and female orgasms may have played a role in our unwillingness to learn more. When you throw in the fact that the majority of researchers behind clinical studies are male, that paints an even clearer picture of why female anatomy isn’t top of mind.
Where our research comes in
At Modern Fertility, our goal is to better understand fertility so we can help people with ovaries plan for their reproductive futures — whatever those look like.
Even in instances where there’s already research around certain aspects of fertility, we find a lot of conflicting information because of the limited number of participants involved. (Privately funded research often means smaller studies simply due to costs.) When we find areas where the research falls short, our research team gets to work.
We’ve published three Modern State of Fertility reports (found here, here, and here), as well as new research presented at the annual American Society for Reproductive Medicine (ASRM) Conference. What’s on the docket? Birth control’s impact on anti-Mullerian hormone (AMH) levels and the factors that affect time-to-pregnancy — both are part of our overall research mission to find a better predictor of future fertility. We’re also committed to partnering with different organizations that focus on supporting race and fertility research and will have more details to share in the near future.
P.S. Check out our research on infertility stigma in the US, fertility knowledge gaps, healthcare providers as fertility information sources, finger-prick fertility hormone testing versus lab testing, and LGBTQ+ individuals’ perceptions of at-home testing.
Contribute to the future of women’s health research
Every Modern Fertility customer is invited to participate in our research. When you purchase a Fertility Hormone Test and opt in to our ongoing research, your anonymized survey responses and hormone levels are made available to our research team. Our team uses this information to study the factors that influence fertility and shares those findings with our customers and the broader scientific community.
And just for fun… a bizarre time in the history of health research
In the late 16th century, a scientist named Marcellus Malpighi saw teeny-tiny organs and tissues in chicken embryos under a microscope. This discovery led to preformationism: the theory that future humans were already formed to some extent in sperm and ovaries.
Then, when scientists Nicolaas Hartsoeker and Anton Leeuwenhoek observed sperm cells under a microscope, they decided that sperm were more likely the homes for preformed humans. In 1694, Hartsoeker illustrated his best guess at what it looked like: a little homunculus in the head of a sperm.
Once microscope lenses improved and we had better research techniques, the preformation theory was traded for Aristotle's theory of epigenesis: the belief that genetic material from people with sperm and people with ovaries joined in the uterus and developed over time into a fetus (aka what we believe today).
Dr. Sharon Briggs, Modern Fertility’s head of Clinical Product Development, contributed to this article.