Amenorrhoea

The absence of menstrual periods. Primary amenorrhoea is defined as failure to start menstruating by the age of 16. Secondary amenorrhoea is the temporary or permanent cessation of periods in a woman who has menstruated regularly in the past. The main cause of primary amenorrhoea is delayed puberty. The delay may not indicate a disorder, but, rarely, it may result from a disorder of the endocrine system, such as a pituitary tumour, hypothyroidism, an adrenal tumour, or adrenal hyperplasia. Another rare cause of delayed puberty is Turner’s syndrome. In some cases, menstruation fails to take place because the vagina or the uterus has been absent from birth, or because there is no perforation in the hymen to allow blood to escape. The most common cause of temporary secondary amenorrhoea is pregnancy. Periods may also cease temporarily after a woman has stopped taking oral contraceptives. Secondary amenorrhoea may also result from hormonal changes due to stress, depression, anorexia nervosa, or certain drugs. Another possible cause is a disorder of the ovary such as polycystic ovary (see ovary, polycystic) or an ovarian tumour. Amenorrhoea occurs permanently following the menopause or after a hysterectomy.