Amenorrhea and chronic anovulation. Finding and addressing the underlying cause.

Amenorrhea is a common problem with a complex etiology. However, the same diagnostic approach can be used in evaluation of all amenorrheic patients. Complete history taking and physical examination are important for determining the presence of congenital abnormalities and chronic conditions. Pregnancy is the most common cause of amenorrhea and should be ruled out in initial laboratory evaluation. Progesterone can then be given to assess endogenous estrogen production and the functioning of the uterus and vagina. Response to this hormone suggests the presence of ovarian, hypothalamic, or pituitary dysfunction, which can be confirmed with further testing. Lack of response to progesterone indicates hypoestrogenism or obstruction of the outflow tract. An estrogen-progesterone challenge helps differentiate these conditions. Chronic anovulation is the second most common cause of amenorrhea. Treatment of chronic anovulation is important to prevent the effects of unopposed estrogen stimulation of the endometrium and to reduce the risk of endometrial adenocarcinoma.