In 2021, tech company Vodafone released its PLAYER.Connect platform in partnership with the Women’s Welsh Rugby Union. The platform uses wearable devices to help players and coaches track health data. Last spring, Vodafone added menstrual cycle data to the platform, enabling teams to view this important health data alongside data on exercise, sleep, stress, injuries, and other information. The company also announced that it would be conducting research with Cardiff Metropolitan University using data gathered by the Women’s Welsh Rugby Union on the platform. This research would “further investigate the impact of the menstrual cycle on areas ranging from concussion and injury prevention to muscle soreness, mood and sleep.”
Also last spring, the University of Birmingham (located in the United Kingdom) announced the launch of a new study on concussion in female rugby players in partnership with biotech company Marker Diagnostics. Female athletes experience a higher rate of concussion than male athletes do, and may also experience more significant and long-lasting symptoms. As a result of the Birmingham research, in April of 2024, Vodafone announced that it was adding a feature to PLAYER.Connect to show concussion data side by side with menstrual cycle data.
The connection between menstrual cycles and concussions
A research review published in March of 2024 looked at “female-specific health considerations in injury and illness surveillance and provide[d] rugby-specific recommendations for future surveillance” [1]. Researchers discussed several areas of women’s health in the article, including concussion. There isn’t yet data on rugby player concussion risk in relation to cycles, but researchers found that female athletes playing other sports appeared to have higher risk of concussion during menstruation or the luteal phase (depending on the study), and lower risk during the follicular phase. The small injury numbers in certain menstrual cycle phases resulted in these studies lacking the appropriate power (there were not enough participants in the study) to consider such a detailed analysis. Changes to the menstrual cycle, including abnormal bleeding patterns, have also been reported after concussion.
The ongoing study from the University of Birmingham plus the Vodafone data are expected to help fill the large knowledge gaps in how concussions impact female hormones, and vice versa.
When is the worst time of the cycle to sustain a concussion?
A 2013 study from the University of Rochester found that women (non-athletes) who experienced a concussion during their luteal phase had a slower recovery and worse health one month after the concussion, compared to women who experienced a concussion during their follicular phase [2]. A university news article about the study also noted that other research has found that “women experience greater cognitive decline, poorer reaction times, more headaches, extended periods of depression, longer hospital stays and delayed return-to-work compared to men following head injury.”
The article also shared some hypotheses about why researchers have found these differences. Of note, sex hormone levels can change following a head injury. Also, stressful events (like a concussion) can “shut down” the pituitary gland, which would cause a woman’s levels of estrogen and progesterone to fall quickly. If a concussion occurs during the luteal phase (when progesterone levels are naturally high), a quick drop in progesterone could create a “withdrawal,” contributing to or worsening concussion symptoms like headache, nausea, dizziness, and difficulty concentrating.
Stressful events (like a concussion) can “shut down” the pituitary gland, which would cause a woman’s levels of estrogen and progesterone to fall quickly. If a concussion occurs during the luteal phase (when progesterone levels are naturally high), a quick drop in progesterone could create a “withdrawal,” contributing to or worsening concussion symptoms like headache, nausea, dizziness, and difficulty concentrating.
One of the researchers noted, “If you get hit when progesterone is high and you experience a steep drop in the hormone, this is what makes you feel lousy and causes symptoms to linger. But, if you are injured when progesterone is already low, a hit to the head can’t lower it any further, so there is less change in the way you feel.”
Lower concussion risk as a “health benefit” of the Pill for female athletes?
A 2018 study found that female college varsity athletes taking hormonal contraception experienced less severe concussion symptoms than peers not taking hormonal contraception [3]. The researchers from the 2013 University of Rochester study offered a plausible explanation as to why this might be: women on the Pill may not experience the previously mentioned progesterone “withdrawal” due to the synthetic progesterone they ingest via their birth control.
One U of R study author stated, “Women who are very athletic get several benefits from the pill; it protects their bones and keeps their periods predictable. If larger studies confirm our data, this could be one more way in which the pill is helpful in athletic women, especially women who participate in sports like soccer that present lots of opportunities for head injuries.”
Protective benefits against concussion aside, what the study author meant by “bone protection” from the Pill is unclear since oral contraceptives are specifically known to decrease bone density, which is especially concerning in young women, who should be at their peak bone density. We addressed the question of whether female athletes are better off on the Pill in greater detail here.
No, women aren’t “small men”….
The ongoing study of gender differences in concussion is one more example of the importance of understanding the differences between male and female bodies (and brains!) and their implications for health—a growing area of study called gender-specific medicine. Until recently, women were considered, for the purposes of scientific research, to be “small men.” This assumption meant that medical treatments that were studied in men were also assumed to be effective and safe for women.
Now, however, we know that this is not true. Men and women have fundamental differences in our physiology and biochemistry that affect our health and how we respond to various medical treatments. As more scientists and doctors consider women to have unique bodies and minds with unique needs, they will be better able to help heal those bodies and minds.
…and we need to adjust our coaching of female athletes accordingly
When it comes to concussion, it’s critical for coaches, trainers, and physicians (not to mention the athletes themselves!) to understand how female athletes differ from male athletes. If there are special considerations when it comes to concussion depending on whether the patient is a male or female, and depending on where a female athlete is in her menstrual cycle when the injury happens, she, her healthcare providers, and her athletic trainers all need to know about them.
“Sports were largely not designed for the female body,” wrote Madison Ayers in a recent Natural Womanhood article. “The cycle is not only impacted by intense activity, but it also works in reverse: the cycle can affect how the female body performs.”
Fortunately, recognition of the importance of gender-specific medicine is growing. As more and more people begin to understand that male and female bodies are meaningfully different, hopefully, female athletes will receive better care, better education, and better coaching—and be both healthier and better athletes as a result.
Additional Reading:
Is it better for female athletes to be on the Pill?
Do female athletes perform worse during their periods?
Gaining ten pounds not only healed my amenorrhea, but made me a stronger runner
Knee surgery, blood clots, and birth control
No, it’s not normal for female athletes to lose their periods
