Why is progesterone taken?
Progesterone is used along with estrogen in women who still have their uterus. In these women, if taken without progesterone, estrogen increases a woman’s risk for cancer of the endometrium (the lining of the uterus). During a woman’s reproductive years, endometrial cells 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 cancer by making the endometrium shed each month. As a result, women who take progesterone may have monthly bleeding. 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) usually do not need to take progesterone.