Gonadotropin-releasing hormone agonists and estrogen-progestogen replacement therapy.

Gonadotropin-releasing hormone agonists are effective in the treatment of endometriosis and myomas, both of which are estrogen-dependent processes, but there is a high clinical recurrence rate after therapy is discontinued. Long-term continuous therapy (2 years or more) has a cumulative effect on bone loss and causes other uncomfortable or harmful side effects. Noninvasive assessments of disease response in patients with myomas have shown that bone changes might be prevented and other side effects of long-term therapy can be alleviated by adding back small amounts of estrogen or progestin. No comparable data are available for patients with endometriosis because the need for repeated laparoscopy has made long-term studies impractical. Nevertheless, a short-term study of patients with endometriosis showed that adding small amounts of progestin during treatment with a gonadotropin-releasing hormone agonist may help prevent bone changes.