Applied Evidence

Should you suspect the female athlete triad?

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Is your patient’s dedication to her sport putting her health at risk? This review—complete with a brief screening tool—will help you identify at-risk athletes and those whose health is already being compromised.




› Screen all adolescent female athletes for components of the female athlete triad at the preparticipation examination or whenever they present with any of the triad’s symptoms. C
› Order a dual-energy x-ray absorptiometry scan to measure bone mineral density on all female athletes with a history of stress fracture—not just those who also have amenorrhea, oligomenorrhea, or disordered eating. C
› Prescribe oral contraceptives to regulate an athlete’s menstrual period only as a last measure for those who, despite following recommendations, do not have a normal return to menses after 6 months. B

Strength of recommendation (SOR)

A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series

CASE › Cassidy, age 14, comes to you for a physical in preparation for track and field tryouts. If she makes the team, she will practice 90 minutes every afternoon with optional practices 2 mornings a week.

She says that her period has been irregular since it started a year ago, and she complains of knee and shin pain that her mother attributes to “growing pains.” She says she usually skips breakfast due to a lack of time in the morning, but eats the school lunches. She is considering becoming a vegetarian. You suspect that the female athlete triad is at work here. How would you proceed?

The female athlete triad (“the triad”) is considered a spectrum of 3 interrelated disorders: low energy availability, menstrual dysfunction, and altered bone mineral density.1 Low energy availability—total dietary energy in (calories in) minus total exercise energy expended (calories out)—is considered the key cause. Previously, the triad was described as disordered eating, amenorrhea (having no menstruation for >3 sequential months), and osteoporosis.2 However, this definition has been expanded to encourage detection before clinical problems progress. In most instances, an athlete will develop only one or 2 of the 3 components of the triad.3,4 This article describes the clinical manifestations of the triad, how to screen patients for it, and indications for referring affected athletes.

How common is the triad?

The prevalence of the triad is difficult to determine because published studies often feature poor standardization of definitions and scales, small sample sizes, and no control groups. In limited studies, the estimated prevalence of female athletes with the complete triad ranges from 1.3% to 4.3%.3,4 Many studies, however, focus on just one of the following 3 components:

Low energy availability. Few studies have specifically evaluated the prevalence of low energy availability among female athletes. The prevalence of disordered eating among females ranges from 25% to 31% of those in “thin build” sports (eg, running, gymnastics, and figure skating) vs 5% to 9% of nonathletes.5,6

Menstrual dysfunction. The prevalence of menstrual dysfunction in female athletes is reported to be as high as 79%.1 Primary amenorrhea (a delay in the age of menarche past age 15) has been reported in 22% of gymnasts, cheerleaders, and divers vs <1% of the general population.7 Subclinical menstrual dysfunction is highly prevalent. For example, one study found 78% of normally menstruating recreational runners had luteal deficiency or anovulation in one-third of their cycles.8

In most instances, an athlete will develop only one or 2 of the 3 components of the triad.Altered bone mineral density (BMD). BMD is increased in most athletes compared to sedentary controls, but low BMD often is seen in amenorrheic athletes. One review found 22% to 50% of amenorrheic athletes had osteopenia vs 12% of controls.9 The prevalence of osteoporosis in this group was as high as 13% vs 2.3% of controls.9

Three interrelated problems

As noted earlier, low energy availability is believed to be the key underlying etiology of the triad. Energy availability is the dietary energy left in the body after exercise is completed, or total dietary energy in (calories in) minus total exercise energy expended (calories out).10,11

Low energy availability is not synonymous with disordered eating. Low energy availability may be the result of either decreased caloric intake or increased output. For example, athletes who increase their training requirements (increased output) need to increase their caloric intake or they will suffer an energy imbalance. Disordered eating also can result in decreased caloric intake. Disordered eating ranges from poor eating habits such as skipping meals to psychiatric conditions such as anorexia nervosa, bulimia, or binge eating disorder. Behaviors may include restricting calories, purging, or using diet pills, diuretics, or laxatives. For a summary of the most recent changes to eating disorder diagnoses, go to

Low energy availability leads to hormonal abnormalities that may exacerbate other triad symptoms. When energy is restricted, the body conserves energy by altering metabolism by several methods, including suppressing usual hormonal cycling. For example, inadequate energy availability results in suppression of gonadotropin-releasing hormone pulsatility and disruption of the number of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) pulses, which results in decreased estrogen levels.12


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