GnRH agonists are one treatment option for fibroids. This treatment shrinks fibroids by blocking hormone production by the ovaries. Because estrogen production is suppressed temporarily, you will experience menopausal symptoms such as hot flashes and vaginal dryness. Treatment is usually limited to three to six months.To offset hot flashes and other uncomfortable menopausal symptoms caused by GnRH agonists, your doctor may add estrogen and/or progesterone therapy.Ask your health care professional to review the risks associated with menopausal hormone therapy and how they may or may not be relevant to your treatment needs for fibroids.