Menstrual issues in young female athletes

Regularly missing periods can often be a sign that young female athletes aren't getting adequate nutrition — which could have potentially serious consequences.

For many girls and young women who compete at the top levels of their sports, not having a regular menstrual period is often seen as a normal part of being an athlete — or even a badge of honor signifying hard work and intense physical training. But the reality is, regularly missing periods can often be a sign that a girl isn't getting adequate nutrition. Her hormone production is likely off balance — which is a problem that could have potentially serious consequences in the near term and throughout life.

Normal reproductive function

A healthy female reproductive system depends on a finely tuned feedback system between three vital organs: the hypothalamus and the pituitary gland — both located in the brain — and the ovaries. These three together are called the hypothalamic-pituitary-gonadal axis.

The hypothalamus kicks off the reproductive cycle by sending out gonadotropin-releasing hormone (Gn-RH), which prompts the pituitary to release follicle-stimulating hormone (FSH). FSH signals a few select immature eggs (follicles) in the ovaries to begin the maturation process. As these follicles mature, they release estrogen. The increased levels of estrogen then signal back to the hypothalamus and the pituitary gland that ovulation — the release of an egg for potential fertilization — is near.

Meanwhile, the pituitary gland is producing another hormone called luteinizing hormone (LH). Shortly before ovulation, a surge of LH prompts the release of the egg. In addition to estrogen, the now-empty follicle begins to produce the hormone progesterone, which helps prepare the uterus for a possible pregnancy.

If the released egg isn't fertilized within 12 to 24 hours, the egg will dissolve and the lining of the uterus will be shed during the menstrual period. Following menstruation, estrogen and progesterone levels are low again, which triggers the hypothalamus to once again release FSH, beginning a fresh cycle.

Missing menstrual periods

A critical component of the ovulatory cycle is an adequate supply of energy. When a girl or young woman doesn't eat enough calories to balance her energy account, her body tries to conserve energy. One way it does this is by suppressing production of the Gn-RH, with the subsequent ripple effects on the pituitary gland and ovaries. The midcycle LH surge may not occur, the follicles will fail to develop normally, and estrogen production falls. As a result, ovulation can occur infrequently — or not at all. The period is usually light or absent. The technical term for this is functional hypothalamic amenorrhea. Amenorrhea means the absence of periods.

For some girls who begin sports training at an early age, intense exercise combined with inadequate nutrition can result in delayed puberty. Girls who haven't had their first menstrual cycle by age 15 are said to have primary amenorrhea. Missing more than three periods in a row after starting regular menstrual cycles is referred to as secondary amenorrhea. Going more than 35 days between periods is called oligomenorrhea.

The physical stress of intense exercise, as well as emotional and psychological stress, can contribute to hormonal abnormalities. Competition can generate stress and anxiety, as can peer pressure, family dynamics and just the challenges of growing up. In response to these and other physical and emotional stressors, the body can release higher levels of hormones such as cortisol and catecholamines (chemicals that affect the nervous system). In addition, the production of growth hormone can decrease. All of these changes can have a negative effect on menstrual function.

Leptin, a hormone produced in fat tissue, is lower in athletes and in women with low body fat. Since leptin stimulates the Gn-RH secretion that initiates menstrual cycles, a leptin deficiency can contribute to not having a normal period.

Genetics can play a role, too. Some girls mature later than other girls do; other girls are more vulnerable to hormonal fluctuations. And it's likely that each girl has a different internal balance point that determines when, or if, hormonal abnormalities occur.

Consequences of missed menstrual periods

Going without periods might not seem like a big deal. After all, the monthly cycle is usually a hassle and often brings bloating, mood swings, painful cramps and other discomforts that get in the way of training.

But missed periods bring consequences. Infertility is one of them. Most adolescents and young women who are serious athletes probably aren't considering when they will become pregnant. But for those who intend to, irregular ovulation during their early years can make becoming pregnant difficult later in life.

Another possible longer lasting consequence of missed periods during adolescence is its effect on bone density. About half of a girl's peak bone mass is acquired during adolescence, with the greatest increase between 11 and 14 years. Many factors contribute to bone density, one of them being estrogen. Girls who have chronically low estrogen levels due to amenorrhea are at risk of having weak bones and of not reaching peak bone mass. The abnormal production of cortisol and growth hormone that can occur as a result of the physical and emotional stress of training can also negatively affect bone density, independent of menstrual function.

Weaker bone structure, obviously, can increase the risk of injuries in the near term. A combination of amenorrhea and demanding workouts greatly increases a female athlete's risk of stress fractures. One study of ballet dancers found that those who practiced more than five hours a day and had amenorrhea all experienced a stress fracture at some point. Such injuries certainly can decrease performance and potentially can derail a career.

Low bone density also has long-term consequences. How likely a woman is to develop weak and brittle bones (osteoporosis) later in life depends partly on how much bone mass she attained in her youth. The higher her peak bone mass, the more bone she has "in the bank" and the less likely she is to develop osteoporosis as she ages.

Nutrition is key

For most female athletes, simply increasing energy consumption to match or slightly surpass the calories that are being expended is enough to restore normal periods. Overeating isn't required, but eating enough is. Because each girl or young woman is different, it can be challenging to pinpoint a specific number or increase in daily calorie intake. The American College of Sports Medicine recommends, in general, a 5 percent increase in weight, or more as needed, to maintain regular periods.

The following suggestions should help girls and young women maintain normal hormonal production and menstruation.

  • Eat regular, nutritious meals. The most important way to ensure normal development is to eat regular, nutritious meals — even if the athlete isn't always that hungry. When eating out, choose options that are filling yet nutritious.
  • Stock up on healthy snacks. A busy schedule might not allow for daily sit-down meals, so keep a stash of healthy snacks that can be grabbed on the go, such as fruit, cut-up veggies, yogurt, cheese and whole-grain crackers.
  • Have a healthy attitude toward food. Look at food in a positive way — as necessary fuel for a healthy body and optimal performance. When a girl or young woman shows signs of an eating disorder — including a severely restricted diet, low self-esteem, and anxiety about weight and body image — consider seeking the help of a counselor or psychologist. Family therapy can be particularly helpful for adolescent athletes.
  • Avoid overtraining and excessive exercise. Exercise should be reduced or stopped entirely until abnormal endocrine function returns to normal, irregular menstrual periods return to normal and a stress-related injury is healed.
  • Get a good night's sleep. Sleep gives the mind and body much needed time to recharge after the day's physical, mental and emotional stresses. It also gives the brain time to encode new memories and learning processes. In adolescents and young adults, deep sleep coincides with the positive release of growth hormone. Lack of sleep, on the other hand, impairs concentration and the ability to perform complex tasks, and also hampers physical performance and reaction time. Don't cheat on sleep — it's too important.
  • Get a handle on stress. Young female athletes are typically juggling many demands and tight schedules. But excess stress can adversely affect hormone production and contribute to menstrual irregularities. Build in time for relaxation, whether it's time to listen to music, spend time with family or friends, take a walk, meditate, or read.
  • See a family doctor, a sports medicine doctor or a pediatrician regularly for treatment and prevention of sport-related risks. A health care professional can help identify potential problems and guide the entire family toward tailored solutions. A health care professional can also provide advice when supplements of calcium and vitamin D might be necessary. Especially for young female athletes who have an eating disorder, it might be necessary to work with a comprehensive care team that includes physicians, psychologists and coaches — all of whom should have experience in treating eating disorders. Inpatient treatment and monitoring might be required for some individuals.
Nov. 04, 2016