Amenorrhea is the complete absence of menstruation, either because it has never appeared before (primary amenorrhea) or because it was stopped after it appeared (secondary amenorrhea).Amenorrhea can be caused by an abnormality in the brain, the pituitary gland, the thyroid gland, the adrenal glands, the ovaries or anywhere in the reproductive system. Normally the hypothalamus(a small part of the brain located just above the pituitary) orders the pituitary to release hormones, which in turn cause the release of eggs by the ovaries.
In certain diseases, the abnormal production of certain pituitary hormones prevents the eggs from being released (ovulation) and can alter the hormonal release sequence that causes menstruation. Likewise, high or low levels of thyroid hormones can cause amenorrhea, reduce the frequency of menstruation or prevent it from starting. In Cushing’s syndrome, the excessive production of cortisol, a corticosteroid hormone, by the adrenal glands causes menstruation to disappear or causes an irregular menstrual cycle.
Strenuous exercise can also suppress menstruation. Probably, the exercise results in a reduction in the secretion of the pituitary hormones that stimulate the ovaries, so they produce less estrogens and, consequently, the menstrual flow is interrupted. The absence of menstruation may also be due to problems in the uterus, such as a hydatidiform mole (a tumor in the placenta) or Asherman’s syndrome (replacement of the uterine lining or endometrium with scar tissue due to infection or surgical intervention).
Some women never reach puberty; therefore, menstruation does not start. Causes include a birth defect that causes an abnormal development of the uterus or fallopian tubes and certain chromosomal problems (for example, Turner’s syndrome, in which cells contain only one X chromosome instead of two). A very uncommon cause is male pseudohermaphroditism, that is, a person who is genetically male becomes a woman. A girl who does not show signs of puberty at the age of 13, who has had no menstruation at the age of 16, or who has had no menstrual flow 5 years after starting puberty should be examined to rule out any clinical problem.
Symptoms vary depending on the cause of the amenorrhea. For example, if the cause was not reaching puberty, normal signs of puberty (such as breast growth, pubic and axillary hair and changes in body shape) will be absent or only partially present. If the cause is pregnancy, the symptoms are morning sickness and an increase in abdominal volume. If thyroid hormone levels are high, symptoms are a rapid heart rate, anxiety and hot, moist skin. Cushing’s syndrome causes the face to have a rounded appearance (face at full moon), the abdomen increases in volume and the legs and arms become thinner. Some causes, such as Asherman’s syndrome, have no symptoms and only manifest as an interruption of menstruation. In polycystic ovary syndrome, some masculine characteristics appear,