The "female athlete triad" is a term used to describe three distinct but interrelated conditions, including, low energy availability, menstrual dysfunction and low bone mineral density. Low energy availability is a term that is used to describe the condition that occurs if a female has low stored energy (low body weight for height), and/or low energy intake (insufficient calorie intake) and/or high levels of energy expenditure (lots of physical activity and/or exercise). The state of low energy availability can result in disruption of the normal menstrual cycle or delay the onset of a female’s first menstrual period. This is referred to as delayed menarche. Delayed menarche is defined as not having had your first menstrual period by age 15. In those females who have had their first period, but have low energy availability, their periods may get farther apart, or they may go away completely. Periods that occur every 35-90 days are referred to as “oligomenorrhea”. Periods that are farther than 90 days apart, or completely absent, are referred to as “amenorrhea”.
Low energy availability may occur unintentionally as a result of inadequate dietary intake relative to very high levels of exercise training. More often, it occurs as a result of intentional dietary restriction in the setting of disordered eating or an eating disorder such as anorexia nervosa or bulimia nervosa. A number of health problems can occur as a result of low energy availability leading to disrupted menstrual function. Infrequent or absent menstrual periods can result in low estrogen levels in the blood, which in turn leads to lower than expected bone mineral density. Amongst athletes, especially those that perform a weight bearing and/or impact sport like long distance running or basketball, the combination of these activities and low bone mineral density increases the likelihood of getting bone stress fractures. Stress fractures are serious injuries and can be a season ending and in some, a career ending injury.
Any female athlete is at risk for the female athlete triad. However, athletes who participate in aesthetic sports like gymnastics, figure skating, diving and dance, or in sports where leanness confers a competitive advantage like long distance running, are more likely to be affected by any component of the triad. We recommend that female athletes in high school and college undergo yearly preparticipation screening with a team physician or sports medicine physician who screens for the triad with the questions listed in Table 1.
Table 1: Female Athlete Triad Preparticipation Physical Evaluation Questions
- Have you ever had a menstrual period?
- How old were you when you had your “first menstrual period ?"
- When was your most recent menstrual period?
- How many periods have you had in the past 12 months?
- Are you presently taking any female hormones (estrogen, progesterone, birth control pills)?
- Do you worry about your weight?
- Are you trying to or has anyone recommended that you gain or lose weight?
- Are you on a special diet or do you avoid certain types of foods or food groups?
- Have you ever had an eating disorder?
- Have you ever had a stress fracture?
- Have you ever been told you have low bone density (osteopenia or osteoporosis)?
Athletes identified as having any one component of the triad, should be carefully screened for the other aspects. While disruption of the menstrual cycle is a relatively common consequence of low energy availability, it’s important to make sure that other conditions are not resulting in menstrual disruption, specifically pregnancy and thyroid disease. Similarly, there are other conditions that can result in lower than expected bone mineral density. These conditions should be considered by a healthcare provider when evaluating an athlete with low bone mineral density.
Comprehensive evaluation of the athlete affected by the triad includes a physical and laboratory evaluation by a healthcare provider. Usually, an evaluation of dietary intake by a registered sports dietitian, and oftentimes an evaluation by a mental health professional, is done, especially if there is evidence of disordered eating or an eating disorder. Bone mineral density is often assessed using a tool called a dual-energy x-ray absorptiometry (DEXA)scan. The DEXA scan provides a number of scores. In the high school, college and young adult female, the “Z-Score” is used to make clinical decisions and NOT the “T-Score”. A Z-Score greater than 0 is normal. A Z-Score between -1 and 0 is still considered normal, but in the setting CONTINUED FROM PAGE 1 of the Triad should prompt discussion about the relationship between low energy availability, menstrual function and bone health – this is especially true if a prior DEXA is available for comparison and was previously greater than 0. A Z-Score between -1 and -2 in a weight bearing athlete is concerning and would indicate that bone health has been negatively affected. A Z-Score less than -2 indicates significant bone loss. Treatment of the triad should be focused on establishing adequate energy availability to meet energy demands of exercise, activities of daily living and in the younger athlete, growth. Although every person’s energy (or calorie) needs are different, research has found that achieving energy availability of 45 kilocalories per kilogram of fat free mass per day is associated with regular menstrual cycles. Fat free mass can be calculated (by measuring body fat percentage) or estimated. An example of this is provided in Figure 1.
Figure 1 : Calculating Energy Availability to Achieve Menstrual Regulation
18 years old
120 lb female
120 lb ÷ 2.2 = 54.5 kg
18% body fat
Fat Mass = 54.5 X 0.18 = 9.8 kg
Fat Free Mass = 54.5 – 9.8 = 44.7 kg
45 kcal X 44.7 kg = 2011 kcal/day
In this example of a 120-lb 18-year-old female, she would require 2011 kcal per day to support healthy reproductive function. A recent paper (2014 Female Athlete Triad Coalition Consensus Statement on Treatment and Return to Play of the Female Athlete Triad) written by members of the Female Athlete Triad Coalition, and published in the British Journal of Sports Medicine, Clinical Journal of Sports Medicine and Current Sports Medicine Reports, and endorsed by several medical professional societies also outlines the use of medications that may be considered in the treatment of women and girls who are affected by the Triad. However, it bears repeating that the primary treatment efforts should be focused on achieving adequate energy intake and adequate stored energy relative to energy expenditure. Medications such as birth control pills to initiate or regulate menstrual function should be used in those cases as outlined in the consensus statement.
The consensus statement also provides physicians with guidance regarding clearance and return to play for athletes affected by the triad. The paper developed a “Magnitude of Risk” tool that includes known risk factors that can be identified and scored leading to Risk Stratification and Recommendations. The risk factors included in this tool include: 1) presence or history of an eating disorder or disordered eating; 2) Current body mass index (BMI); 3) Age of first menstrual period; 4) Number of menstrual periods in the past 12 months; 5) Bone mineral density as measured by DXA scan; 6) History of bone stress fractures or stress reactions. Using the Magnitude of Risk and Risk Stratification tools, a physician can then inform the athlete where she lies on the continuum, and develop a plan to achieve health and guide safe participation in sports or exercise. In conclusion, exercise and sport participation improve health and quality of life for females of all ages.
The female athlete triad can be a consequence of participation, the same way that knee injuries can be a part of football participation. We should not discourage females from participating in sport, instead we should screen for risk factors and the conditions that make up the triad, and treat it appropriately.