The pathophysiology of exercise-associated amenorrhoea is complex, with bodyweight loss, lowered body fat plus emotional and physical stress all playing a role. The amenorrhoeic athlete exhibits decreased levels of the gonadotropic hormones (follicle-stimulating hormone and luteinising hormone) and the reproductive hormones (estrogen and progesterone). The low estrogen levels in both athletes with amenorrhoea and postmenopausal women have been linked to a reduction in bone mass.
Osteoporosis, the third part of the triad, refers to inadequate bone formation and premature bone loss, resulting in low bone mass and increased risk of fracture. Women with amenorrhoea, both athletes and nonathletes, have been shown to have lower vertebral bone mineral densities (BMD) compared with healthy women.
Studies have shown that bone mineral densities in the femoral midshaft and tibia, femoral neck and lumbar spine are lower in athletes with amenorrhoea. In addition, it has been shown that vertebral BMD in athletes with amenorrhoea is 20 percent lower than in healthy athletes and 10 percent lower than in cyclic nonathletes of a similar age.
Research in the past 10 years has also indicated that premature osteoporosis in women with amenorrhoea is partially irreversible despite resumption of menses, estrogen replacement or calcium supplementation.
Screening and Prevention
Prevention of the triad disorders starts with awareness. A pre-participation physical examination presents an ideal opportunity for a sports physician to screen for any potential problems. The physician should screen for disordered eating by asking the athlete to recall what she has eaten during the last 24 hours and to list any forbidden foods.
The athlete's highest and lowest bodyweight should also be ascertained, and the athlete should be asked if she engages in any disordered eating patterns such as bingeing or purging. The physician should also obtain the athlete's menstrual history, including age of menarche, frequency and duration of cycles, last period and usage of hormone therapy. A laboratory examination can also be done to measure levels of hormones in the blood.
Treatment is based on the results of the work-up and follow-up scans. Maximum bone loss probably occurs in the early phase of amenorrhoea, and treatment should, therefore, be initiated soon after the diagnosis is made.
For athletes with amenorrhoea and low bone mass, the preferred treatment is a decrease in exercise intensity or a two- to three-percent gain in body weight. In addition, the athlete must maintain a daily calcium intake of 1200 to 1500 mg per day. The calcium intake can be accomplished by adding three glasses of skimmed milk per day to the diet or by taking supplemental calcium.
A program of resistance training designed to increase both muscle mass and strength may improve the skeletal muscle profile of these athletes. Finally, estrogen replacement therapy (ERT) may be required for those athletes who are not willing to make changes to their dietary or exercise programs.
Waldrop, J. Early identification and interventions for female athlete triad. 2005. Journal of Pediatric Health Care. 19 (4), 213-220.