Amenorrhoea is defined as the failure to menstruate. It can be classified as primary (menstruation fails to start) or secondary, which is defined as the cessation of periods for greater than 6 months. Amenorrhoea may be due to the absence of the uterus as in an XY female, blockage of the outlow tract owing to an imperforate hymen, or endometrial disturbances, i.e. absence as in uterine scarring (Asherman syndrome) atrophy as in premature menopause, or hormonal imbalance as in polycystic ovarian syndrome.

Primary: Primary Amenorrhoea has been mentioned in disorders of puberty

Secondary: The most common causes of secondary Amenorrhoea are hypothalamic suppression Hyperprolactinaemic (usually due to a Prolactinoma, Tumor of the pituitory gland), or polycystic ovary. Other causes include thyroid disease, adrenal disease, premature ovarian failure and Sheehan syndrome. Sheehan syndrome is a form of hypopituitarism causes by post partum schaemic necrosis of the anterior pituitary. The Hyperplastic pituitary gland at pregnancy is more susceptible to hypertension and severe post partum haemorrhage may precipitate Sheehan syndrome. Asherman syndrome should be suspected in women who have Amenorrhoea and have normal hormonal profiles with evidence of ovulation, particularly in women who have had some form of uterine surgery, for example termination of pregnancy or dilatation and curettage (D&C) which could precipitate the formation of intrauterine adhesions.

Pregnancy and natural menopause are physiological courses of Amenorrhoea. When a woman presents with secondary Amenorrhoea pregnancy and natural menopause should always be considered.