Amenorrhea

Diagnosis

Abnormal absence of menstrual periods is called amenorrhea.

Amenorrhea is normal in girls before puberty and in women during pregnancy, while breastfeeding, and after menopause. The absence of menstrual periods when periods are normally expected, however, is an abnormal condition.
Amenorrhea is classified as primary or secondary. The disorder is classified as primary amenorrhea if a healthy young woman has not started having menstrual periods after puberty, typically by 16 years of age. Secondary amenorrhea refers to periods that have been absent for longer than 3 months in a nonpregnant adult woman who previously had been menstruating.
If a young woman has not gone through any changes associated with puberty (such as pubic hair growth and breast development) and is not having any periods, she should be evaluated by age 13. Most young women begin menstruating by 14 years of age.

Menstrual cycle disturbances are one of the most common complaints causing women of reproductive age to seek medical care.

An estimated 2% to 5% of women in the general population have amenorrhea. The prevalence is even higher in female athletes; an estimated 66% of these women do not get their periods.

Hormonal imbalances can inhibit normal menstruation.

A part of the brain called the hypothalamus is responsible for producing a hormone called gonadotropin-releasing hormone (GnRH). Appropriate amounts of GnRH allow the reproductive system to operate normally. Stress, both physical and emotional, can inhibit the normal release of GnRH from the hypothalamus. This results in "hypothalamic amenorrhea", the most common cause of amenorrhea in women.
Thyroid malfunction—either hyperthyroidism, in which too much thyroid hormone is secreted, or hypothyroidism, in which thyroid hormone production is diminished—can also cause amenorrhea.
Imbalances of the hormone prolactin can also lead to amenorrhea. Prolactin is a pituitary hormone that is normally produced to allow for lactation after giving birth. In a woman who is not pregnant, however, prolactin elevations are abnormal. In most cases, prolactin overproduction is due to a small, benign growth (microadenoma) on the pituitary gland. Some medications can also elevate prolactin levels and cause amenorrhea.

Emotional and physical stress and eating disorders—including anorexia nervosa, bulimia, extreme dieting, and starvation—can upset the body's hormonal balance and cause menstrual periods to stop.

Excessive exercise and strenuous athletic activities also cause hormonal imbalances that result in amenorrhea.

Amenorrhea can be a side effect of other disorders.

Very obese women sometimes do not menstruate because excess fat cells can interfere with ovulation.
Cushing's syndrome—a very rare disorder caused by increased secretion of a steroid hormone (cortisol)—is characterized by amenorrhea, as is polycystic ovary syndrome. Polycystic ovary syndrome is a very common disorder characterized by multiple ovarian cysts.
In some women, menopause occurs prematurely, before the age of 40. In these cases, premature ovarian failure is the cause of the amenorrhea.

Amenorrhea may be a side effect of certain drugs, including sedatives, hormones, oral and injectable contraceptives, barbiturates, and narcotics. Some women stop having menstrual periods for several months after they stop taking birth control pills.

Amenorrhea can be caused by various anatomic and genetic conditions Figure 01.

While there is usually a small opening in an intact hymen (the membrane that covers the vaginal opening), some women have a hymen that contains no opening at all. In such cases, menstrual flow cannot pass out of the body.
Figure 01. Female reproductive anatomy
Some girls do not go through puberty, and do not begin having menstrual periods. In rare situations, a young woman may lack certain female organs (such as the vagina, uterus, or ovaries), or these organs may not be formed normally.
Disorders of the uterus such as Asherman's syndrome, which is characterized by adhesions or scarring within the endometrial cavity, can cause amenorrhea and infertility.
Women who have been injured, who have autoimmune disorders or pituitary tumors, or who have undergone chemotherapy, may experience ovarian failure that results in amenorrhea.
A genetic disorder may also be the cause of amenorrhea. For example, women with Turner's syndrome have one X chromosome instead of two. This abnormality prevents the woman from going through normal sexual maturation. Consequently, menstrual periods do not occur. Another genetic disorder, androgen insensitivity syndrome (also called testicular feminization), affects the development of the reproductive organs. In women with androgen insensitivity syndrome, the genitalia may look normal, but the internal organs are undeveloped. Because these women have no ovaries or uterus, they cannot menstruate or become pregnant.

The symptoms of primary and secondary amenorrhea differ.

In primary amenorrhea, a young woman who has had the normal body changes associated with puberty has not begun to menstruate by age 16. In secondary amenorrhea, the normal menstrual periods of a woman who is not pregnant become irregular and abnormal or stop altogether for 3 to 12 months.

Risk for amenorrhea increases with intense exercise and poor nutrition. Other risk factors for secondary ammenorrhea include obesity, use of certain hormones, and thyroid disease.

Young women who participate in highly competitive sports are at risk for amenorrhea. That is because these athletes often have a low body fat content (less than 15% to 17%) that, combined with the psychic stress associated with exercise, can cause menstrual periods to stop. Young women who participate in sports that encourage excessive thinness, such as gymnastics, are also at increased risk for developing anorexia. Women not engaged in competitive athletics may decide to start exercising vigorously to lose weight and get in shape, and consequently develop secondary amenorrhea. While physical fitness is important, exercising and dieting to the point where menstruation stops puts you at increased risk for osteoporosis.
In general, the socially desirable body size for women is quite thin. A weight for height that is lower than 90% of "normal" (the rule of thumb is to allow 100 lbs for the first 5 feet and 5 lbs for each inch above 5 feet) indicates that the low body weight might be associated with the menstrual disorder Figure 02.
Figure 02. BMI calculator

A complete history and physical examination are the first steps in establishing the cause of amenorrhea.

Proper management of primary or secondary amenorrhea depends on a precise diagnosis.
The provider will ask questions about the patient's overall growth and development, any family history of genetic abnormalities, lifestyle and potential stress factors, exercise behaviors, and eating habits.
The provider will then perform a physical examination to determine whether normal puberty has occurred, and to look for initial evidence of other causes of amenorrhea. This usually includes a pelvic examination. During the pelvic exam, the physician visually inspects the external genitals and the inner walls of the vagina and cervix. The physician also touches the abdomen to determine whether the uterus, ovaries, and other organs are the proper size and in the proper position, and to detect the presence of cysts or tumors. Sometimes, an ultrasound examination can be performed instead of a pelvic examination.

The provider will order various laboratory tests, depending on the suspected cause of amenorrhea.

These may include blood tests to determine hormone levels, and to assess thyroid and adrenal function. A buccal smear, in which cells are scraped from the inside of the cheek, is often taken in order to study the patient's chromosomes. The possibility of pregnancy should be eliminated right away and confirmed with a laboratory test.

Some patients require computed tomography (CT) or ultrasound scanning if tumors are suspected. In some cases, surgical diagnostic procedures such as laparoscopy are required to determine the cause of the problem.

Eating properly and maintaining appropriate body weight is important.

Restoring adequate body weight and achieving normal eating patterns is essential. Some women may benefit from psychological counseling to help reach these goals.

Avoid taking any drugs that are not prescribed.

Because certain drugs can trigger menstrual disorders, including amenorrhea, be sure not to take any drugs that have not been prescribed by your physician.