Akademik

the absence or stopping of the menstrual periods. It is normal for the periods to be absent before puberty, during pregnancy and milk secretion, and after the end of the reproductive period (see menopause). In primary amenorrhoea the menstrual periods fail to appear at puberty. This may be due to absence of the uterus or ovaries, a genetic disorder (e.g. Turner's syndrome), or hormonal imbalance. In secondary amenorrhoea the menstrual periods stop after establishment at puberty. Causes include disorders of the hypothalamus (a part of the brain), deficiency of ovarian, pituitary, or thyroid hormones, mental disturbance, depression, anorexia nervosa, or a major change of surroundings or circumstances.