What are estrogen and progesterone?

Estrogen and progesterone are hormones that are produced by a woman's ovaries.

Why does the body need estrogen?

Estrogen thickens the lining of the uterus, preparing it for the possible implantation of a fertilized egg. Estrogen also influences how the body uses calcium, an important mineral in the building of bones. In addition, estrogen helps maintain healthy levels of cholesterol in the blood. Estrogen is necessary in keeping the vagina healthy.

As menopause nears, the ovaries reduce most of their production of these hormones. Lowered or fluctuating estrogen levels may cause menopause symptoms such as hot flashes, and medical conditions such as osteoporosis.

What is hormone therapy (HT)?

Hormone therapy (HT) is a treatment that is used to supplement the body with either estrogen alone or estrogen and progesterone in combination. When the ovaries no longer produce adequate amounts of these hormones (as in menopause), HT can be given to supplement the body with adequate levels of estrogen and progesterone. HT helps to replenish the estrogen, relieving some of the symptoms of menopause and helping to prevent osteoporosis.

Why is progesterone taken?

Progesterone is used along with estrogen in women who still have their uterus. In these women, estrogen-- if taken without progesterone--increases a woman's risk for cancer of the endometrium (the lining of the uterus). During a woman's reproductive years, cells from the endometrium are shed during menstruation. When the endometrium is no longer shed, estrogen can cause an overgrowth of cells in the uterus, a condition that can lead to cancer.

Progesterone reduces the risk of endometrial (uterine) cancer by making the endometrium thin. Women who take progesterone may have monthly bleeding, or no bleeding at all, depending on how the hormone therapy is taken. Monthly bleeding can be lessened and, in some cases, eliminated by taking progesterone and estrogen together continuously. Women who have had a hysterectomy (removal of the uterus through surgery) typically do not need to take progesterone. This is an important point, because estrogen taken alone has fewer long-term risks than HT that uses a combination of estrogen and progesterone.

What are the types of hormone therapy (HT)?

There are two main types of HT:

  • Estrogen Therapy (ET) : Estrogen is taken alone. Doctors most often prescribe a low dose of estrogen to be taken as a pill or patch every day. Estrogen may also be prescribed as a cream, vaginal ring, gel or spray. You should take the lowest dose of estrogen needed to relieve menopause symptoms and/or to prevent osteoporosis. This type of HT is used if a woman has had a hysterectomy
  • Estrogen Progesterone/Progestin Hormone Therapy (EPT) : Also called combination therapy, this form of HT combines doses of estrogen and progesterone (progestin is a synthetic form of progesterone). This type of HT is used if a woman still has her uterus
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