Amenorrhea and Bone Health in Disordered Eating

It's not uncommon for people to be less than excited about getting their menstrual period. However, eating disorder treatment professionals are usually thrilled when a patient’s menses return after it has stopped due to an eating disorder.

Although amenorrhea has been removed from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) as a diagnostic criterion for anorexia nervosa, it remains a significant marker of the illness for many.

It is important to note eating disorders don't discriminate based on sex or gender—anyone can experience an eating disorder. In fact, men experience eating disorders at higher rates than were once thought. It bears noting that there is no equivalent to amenorrhea among males with eating disorders. Males often experience decreased testosterone, which can cause its own set of symptoms. This article, however, will address only amenorrhea related to eating disorders.

Causes

Of females with anorexia nervosa between 66% and 84% experience amenorrhea, with an additional 6% to 11% experiencing light or infrequent menstrual periods. Approximately 7% to 40% percent of females with bulimia nervosa report amenorrhea. A younger adolescent may experience a delayed start of their first period as a result of an eating disorder.

Amenorrhea occurs most commonly when the body is in a state of "relative energy insufficiency," in which caloric intake is inadequate relative to energy burned. This state disrupts the hormone cycle that regulates menses. Some people with anorexia, however, continue to menstruate throughout their illness. Others stop menstruating even before they start losing weight due to their illness. Binge eating has also been found to cause menstrual disturbances.

The cessation of periods in people with an eating disorder mimics the onset of menopause. Associated symptoms may include:

• Cognitive problems
• Difficulty sleeping
• Mood changes
• Night sweats
• Shrunken ovaries and uterus

One of the most significant effects of these hormone changes is osteopenia, which is a depletion of calcium in the bones. Depleted bones are a major concern because they fracture at higher rates. In the longer term, osteopenia may lead to irreversible and chronic problems such as osteoporosis (brittle bones).

Treatment

The safest and most effective strategy to improve bone density issues related to anorexia nervosa is returning to a weight that is appropriate as per growth chart and history, and natural restoration of menstrual function.

In females, bones will not grow stronger without adequate estrogen, which requires a resumption or initiation of menstruation. The only treatment for the resumption of menses is adequate and sustained weight restoration through refeeding and normalization of eating (including cessation of binge and purge cycles).

In many cases in which patients have improved and have been presumed cured, amenorrhea persists. It may take up to six months for menses to resume after weight has been restored. Persistence of amenorrhea beyond this point may indicate the individual is not truly fully weight restored.

A 2013 study by Faust and colleagues demonstrated that standard eating disorder treatment goals may be insufficient to resolve amenorrhea. This study notes that the standard treatment goal for adult patients is achieving 90% of expected body weight (based on body mass index, height, age, and sex). But among adolescents with anorexia nervosa in the study, the return of menses occurred on average at about 95% of expected body weight, suggesting that the standard goal is too low to successfully restore menses for many.

Study authors noted that "individual differences in weight trajectories should be taken into account," since ​many patients may have higher setpoints (and hence, weights at which menses will resume) than population averages would suggest. It is not atypical for adolescents to restore menses at weights more than 5 pounds above the weight that supported menses prior to the onset of amenorrhea.

Unfortunately, for some patients, depending on the length, severity, and age at onset of illness, bone density may never be fully recoverable, but the chances are greatly improved by early and aggressive treatment.

Myths About Amenorrhea and Bone Density

The following are just a few of the many myths about amenorrhea and bone loss due to an eating disorder.

Myth: Birth control pills can solve the problem of amenorrhea due to an eating disorder

Fact: Birth control pills are commonly prescribed in an attempt to restart menses and to minimize bone weakness. One study surveyed doctors and found that 78% prescribed birth control pills for their patients with anorexia nervosa. However, research shows that birth control pills do not help to reverse osteopenia.

They cause only an artificial period and do not get at the heart of the problem or help with bone density. In fact, because the pills may mask the problem (lack of true menstruation), they are not recommended for purposes beyond birth control (non-menstruating sexually active females may still become pregnant).

Myth: Exercise will strengthen the bones of females with eating disorders and amenorrhea

Fact: Although weight-bearing exercise usually helps to strengthen and build bone, this does not hold true for patients with anorexia nervosa.

Misra and colleagues wrote: "[Once] they become amenorrheic, the protective effect of exercise is lost. To date, there is no evidence that high-intensity exercise in the context of weight loss and amenorrhea is protective to bone mass in [anorexia nervosa]."

Furthermore, excessive exercise may lead to estrogen deficiency and amenorrhea, exacerbating the problem.

A Word From Verywell

Loss of menses during an eating disorder is a significant cause for concern that is best remedied by prompt weight restoration, normalization of eating behaviors, and sustained nutrition.

If you or someone you love believes she is fully recovered but is not experiencing menstrual periods, it is a good idea to talk with your health care professional who may work with you to increase your weight to see if menses return. This offers the best opportunity for reducing lifelong debilitating consequences resulting from bone weakness.