polycystic ovary syndrome (PCOS), an endocrine disturbance characterized by anovulation, amenorrhea, hirsutism, and infertility. It is caused by increased levels of testosterone, estrogen, and luteinizing hormone (LH) and decreased secretion of follicle-stimulating hormone (FSH). The increased level of LH associated with this disorder may be the result of an increased sensitivity of the pituitary to stimulation by releasing hormone or of excessive stimulation by the adrenal gland. It may also be associated with a variety of problems in the hypothalamic-pituitary-ovarian axis, with extragonadal sources of androgens, or with androgen-producing tumors. This condition is transmitted as an X-linked dominant or autosomal-dominant trait. The depressed but continuous production of FSH associated with this disorder causes continuous partial development of ovarian follicles. Numerous follicular cysts, 2 to 6 mm in diameter, may develop. The affected ovary commonly doubles in size and is invested by a smooth pearly white capsule. The increased level of estrogen associated with this abnormality raises the risk of cancers of the breast and endometrium. Depending on the severity of symptoms and the patient’s desire to become pregnant, treatment involves suppression of hormonal stimulation of the ovary, usually by use of female hormones or resection of part of one or both ovaries. Also called hyperandrogenic chronic anovulations, Stein-Leventhal syndrome.
