Whether you are on a gymnastics team or train for triathlons, when you’re a female athlete, being at peak physical performance is important. But can your period mess with that? If you have painful cramps or lose too much blood while on your period, can’t those hinder your athletic ability? For many female athletes, birth control is prescribed to reduce pain and blood loss in hopes of improving physical performance. But a recent study by Massey University in New Zealand suggests there may be birth control health risks for female athletes worth considering [1].
Why study female athletes?
Inflammation in the body can have a profound effect on overall health and the risk of cardiovascular disease. An effective way to measure this risk is through the body’s production of C-Reactive Protein (CRP). The Massey University study evaluates if female athletes on birth control are more likely to have long term inflammation and an increased risk of cardiovascular disease (measured by a CRP level of >1mg/L).
But why study elite female athletes, instead of female non-athletes? Previous studies show that while birth control increases inflammation and cardiovascular disease risk in females, exercise can reduce both naturally [2]. So, it’s an interesting question to consider whether birth control can still increase CRP levels in elite athletes who routinely participate in exercise and endurance training.
What the Massey study found about inflammation and cardiovascular disease risk in female athletes
Sixteen elite female athletes (cyclists and triathletes) offered blood samples at two coordinated points in their menstrual cycles. Nutrition, exercise, and rest were all controlled. Half of the athletes were naturally menstruating, while the other half were on birth control (and had been for at least 12 months prior). Because of the impact of age on CRP production, those in the birth control group were roughly 10 years younger than those naturally menstruating. The study authors didn’t clarify why they chose to “account for” age in this way for the women on birth control but not the ones who were naturally cycling.
Any CRP result greater than 1mg/L suggests a risk of cardiovascular disease (which could mean heart disease or disease of the blood vessels) and long term inflammation. Elevated CRP suggests “increased risk of endothelial [lining of the blood vessel] damage, myocardial infarction [heart attack], thromboembolic events [blood clots], and atrial fibrillation [irregular, often fast heartbeat],” the Massey researchers stated [1]. The study found that female athletes on birth control had mean CRP levels at least two times higher than those naturally menstruating, suggesting they are more likely to experience blood clots, strokes, and heart attacks.
The relationship between birth control and blood clots isn’t ‘new’ news
While disturbing, this isn’t breaking news: studies have long shown a relationship between birth control use and increased risk of blood clots. But this study confirms that, while exercise plus endurance training can reduce CRP production (and therefore decrease inflammation and cardiovascular disease risk), it simply cannot overcome the increased amount of CRP caused by consistent birth control use.
The Massey University study was admittedly small, with a sample size of only sixteen women. Further testing with a larger sample size would be beneficial down the road. However, the study isn’t the first of its kind. Previous studies measuring CRP levels in female athletes on and off of birth control have produced similar results, indicating that consistent birth control users are more likely to have increased inflammation and cardiovascular risk than those naturally menstruating, despite their exercise routines [3].
What about athletes with heavy periods? Can’t birth control help prevent iron deficiency?
Although the age range of participants in this study varied by approximately ten years, these results may be especially important for young female athletes. The first few years of menstruation can be irregular, and blood flow may be heavy. Hormonal birth control is frequently offered to “regulate” periods and reduce heavy period flow, sometimes in an effort to prevent or mitigate iron deficiency.
As with previous research, the Massey study did not find significant differences in iron levels for female athletes on birth control versus those naturally menstruating. The authors of the study note that while this may be influenced by the specific brand and duration of birth control used, there are other factors for athletes that may equally impact iron levels. These include their exercise routine and dietary choices (vegan, vegetarian, macronutrient-restrictive, etc). Research should continue to find a definitive answer.
The bottom line: Fertility awareness serves female athletes far better than birth control can
While the Massey study did not show a decrease in iron deficiency for birth control users, it did show an increase in cardiovascular risk, even in highly-conditioned elite athletes. The younger birth control use begins, the longer a female athlete is likely to be on it, and the longer she will be subject to its attendant risks of blood clots, heart attack, or stroke. Her teen and young adult years are furthermore a critical time to accrue bone mass density (which birth control use interferes with), which may impact athletic ability and mobility throughout her lifetime.
An alternative to birth control for female athletes with heavy periods or irregular cycles is partnership with a restorative reproductive medicine-trained gynecologist who can get to the root cause of cycle issues. Charting menstrual cycles through a Fertility Awareness Method can not only help athletes predict their next period, but can help trained gynecologists pinpoint underlying medical issues that may be leading to heavy or painful periods and impacting physical performance. Addressing these issues at their root may improve athletic ability and long term health without increasing inflammation and cardiovascular risk, as birth control appears to do.
References:
[1] Shanahan, Lilly et al. “Sex-differentiated changes in C-reactive protein from ages 9 to 21: the contributions of BMI and physical/sexual maturation.” Psychoneuroendocrinology vol. 38,10 (2013): 2209-17. doi:10.1016/j.psyneuen.2013.04.010 [2] Ford, Earl S. “Does exercise reduce inflammation? Physical activity and C-reactive protein among U.S. adults.” Epidemiology (Cambridge, Mass.) vol. 13,5 (2002): 561-8. doi:10.1097/00001648-200209000-00012 [3] Cauci, S., Francescato, M.P. & Curcio, F. Combined Oral Contraceptives Increase High-Sensitivity C-Reactive Protein but Not Haptoglobin in Female Athletes. Sports Med 47, 175–185 (2017). https://doi.org/10.1007/s40279-016-0534-9Additional Reading:
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