As women age, their bodies produce significantly decreased levels of estrogen. It has been used to relieve the symptoms of menopause, such as hot flashes, sweats, disturbed sleep, and an increased rate of bone loss. It is also believed to be useful in preventing heart disease in women. Today, this term is used to describe treatment with either estrogen alone or with estrogen and another hormone called progestin.
Hormone therapy goes by various names, depending on the hormones used.
Estrogen replacement therapy refers to treatment that uses only estrogen. Some women may have side effects from HRT, such as unusual vaginal bleeding, headaches, nausea, vaginal discharge, fluid retention, swollen breasts, weight gain, and abnormal vaginal bleeding. These side effects are still being studied. Long term use of HRT has been linked to breast cancer in some studies. When estrogen is taken alone, there appears to be a risk of cancer of the uterus.