Center for Young Women's Health

Sports and Menstrual Periods:

The Female Athlete Triad


Getting Treatment:
The Reproductive Endocrine Practice at Boston Children's Hospital offers special services in the diagnosis and treatment of hormonal health problems due to sports related activities.

Today, more and more adolescent girls and young women are taking part in sports. As a result, they are healthier, in better shape, and more active. Being active improves cardiovascular (heart) fitness, bone strength, and overall health.


Most girls who play sports have regular menstrual periods, and girls who are very active may skip a few periods. However, some girls who train really hard may skip many menstrual periods, or they may get their period at a late age, especially if they've lost weight or developed an eating disorder. Girls may begin to skip periods if they are not getting proper nutrition, or if there is too much stress on their body from sports. This stress lowers estrogen levels, which may cause skipped periods. Low estrogen levels and a lack of menstrual periods can lead to low bone mass and stress fractures (small cracks) in your bones.


What is the Female Athlete Triad?

Recently, doctors, athletes, and coaches have used the term "Female Athlete Triad" (triad means three) to refer to athletic girls who have the following:


1. Inadequate nutrition: Inadequate nutrition means that your body is not getting enough energy from the foods you eat. Even eating regular amounts of food may not be enough for a very active person to maintain a normal weight. Some girls don't eat enough calories throughout the day, and others don’t eat enough healthy fats. Healthy nutrition is needed to have regular periods and normal estrogen levels. If you lose weight, you are especially likely to skip periods. Some girls with the Female Athlete Triad also have an eating disorder such as anorexia nervosa or bulimia. When a girl or young woman with anorexia nervosa or bulimia does too much exercise, she is putting an extreme strain on her body.


2. Amenorrhea: This is defined as the absence of menstrual periods for longer than 6 months. This lack of menstrual periods can happen when there is weight loss, disordered eating, or intense training or exercise. A certain percentage of body fat is healthy for the body, and girls will stop their periods if their weight drops to an unhealthy level, or their nutrition is not balanced. Having your period every 2 to 3 months or very light periods is a sign that you are not taking in enough nutrients.


A healthy weight is especially important for you to have normal levels of the female hormone estrogen. Normal levels of estrogen are important for your body to absorb calcium (a mineral your body needs to build strong bones). Not enough estrogen can cause low bone mass.


3. Low Bone Mass: This is when your bones are weaker than they should be. Although physical activity helps to build a healthy skeleton and strong bones, too much exercise can cause problems if you are not having regular periods and normal estrogen levels. Everyone (teen girls especially) needs the right balance of exercise, body weight, calcium intake, vitamin D, and estrogen levels to have healthy bones.


What health problems can the Female Athlete Triad cause in the future?

Each of the three conditions (inadequate nutrition, amenorrhea, and low bone mass) are serious problems that can cause problems in the future and need medical care. Even if you only have one or two of the conditions, it's important to talk about them with your healthcare provider. For example; athletes may eat a healthy diet and yet still skip menstrual periods and be at risk of low bone mass.


Disordered eating can cause heart problems such as an irregular heart beat, muscle weakness or fatigue, fainting, and loss of concentration with school work and athletics.


Amenorrhea is a sign that your body is not functioning properly. The biggest concern is that low estrogen levels may result in low bone mass.


Ensuring normal bone mass is very important. The teen years are the most important time in a girl's life for developing normal, strong bones. Girls should add half of the bone mass that they will have for their lifetime during their teen years. Very little bone mass is added after you are 20 years old, and so the teen years are very important for getting the right amount of bone for your lifetime.


During your teen years, weak bones and intense exercise can make it easier for you to get stress fractures. A stress fracture is a very small crack that can occur in bones when you do the same activity over and over for too long. For example, a runner may get a stress fracture in her lower leg or foot, and a gymnast may get a stress fracture in her spine. If you continue to do the activity in spite of the pain, the bone may break.


How will I know if I have low bone mass?

If you are skipping periods and your healthcare provider is worried about low bone mass, he/she may suggest that you have a test that tells whether your bones have lost thickness or strength. One of these tests is called a DXA (Dual Energy X-Ray Absorptiometry) scan. It is a painless test that uses low radiation waves to take a picture of your bones. The test results tell your healthcare provider whether you have more or less bone mass than other girls your age.


Who is at risk for the Female Athlete Triad?

Athletes who do a great amount of physical activity are at risk for any of the three conditions of the Female Athlete Triad. Athletes who are very competitive or focus a large part of their lives on their sport are considered to be at a higher risk. Certain activities that involve a lot of endurance (such as long distance running) may put you at more risk for the Triad. There is also a higher risk among girls involved in activities that demand a thin physical appearance, such as gymnastics or dancing. Being aware of these demands or pressures on your body is a good first step towards keeping yourself healthy. It's important to remember to balance your sports activites and nutrition. The right balance will keep you healthy.


What should I do if I'm a female athlete?

Taking part in sports is a great way to be active and to improve your health. As long as you take care of yourself and talk to your health care provider when you have questions or problems, sports will make you a stronger, fitter, and healthier person.


Written and reviewed by the CYWH Staff at Boston Children's Hospital


Updated: 5/21/2010


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