Estrogen replacement therapy is one of the most controversial issues in the field of reproductive medicine. Indications for its use include hot flashes, vaginal atrophy, and risk of osteoporosis. Risk of heart disease may also be an indication but this use has not been firmly established. The role of estrogen replacement therapy in aging changes of skin needs clarification. Complications of therapy include endometrial cancer, breast cancer, hypertension, hyperlipidemia, and gallbladder disease. The last three complications presumably result from hepatic actions of estrogen replacement therapy.
PIP: Indications and complications of estrogen replacement therapy are discussed in this edited transcription of a conference held at the UCLA School of Medicine. Although many of the symptoms of loss of ovarian function can be corrected by estrogen replacement therapy, several potentially harmful side effects are associated with the administration of estrogen. Hot flashes, the most common menopausal symptom for which women seek treatment, may continue over extended periods of time and the loss of ovarian feedback signals. Several types of evidence indicate that hot flashes are centrally rather than peripherally mediated disturbances, and it now appears that the hypothalamic factors which stimulate pulsatile release of luteinizing hormone play an integral role in initiation of hot flashes. The fact that the extent of estrogen deficiency differs among postmenopausal women may explain why all women do not have hot flashes. The effects of body size on estrogen production and plasma protein binding appear to be significant variables modulating the extent of estrogen deficiency and hypothalamic function. Other studies suggest that calcitonin and gonadal steroids are linked in the pathogenesis and treatment of osteoporosis, but the mechanism of action of estrogen replacement therapy in the treatment of osteoporosis has not been elucidated. Most investigations have failed to show the presence of estrogen receptors in bone. It is likely that the term osteoporosis includes heterogeneous skeletal disorders and that both sex hormones and calcemic hormones are important in pathogenesis. Further research is required on the possible effect of estrogen replacement therapy in decreasing relative risk of arteriosclerotic heart disease. Vaginal atrophy is an accepted indication for estrogen replacement, but its use for skin indications should not be recommended until a beneficial cosmetic effect is shown. Complications of estrogen replacement include endometrial cancer, breast cancer, hypertension, hyperlipidemia, and gallbladder disease, the latter 3 apparently resulting from hepatic action of estrogen replacement therapy. Because of the enhanced hepatic action of orally administered estrogen, other routes of administration are being explored. Additional research is needed to define the risk-benefit ratio of estrogen replacement therapy.