What is progesterone?

Progesterone is a hormone; it is produced, along with estrogen, by the ovaries.   Watch the animation to learn more about progesterone and the ovaries.

Progesterone is a female hormone that prevents the lining of the uterus from thickening. It is used as part of hormone replacement therapy in post-menopausal women. In hormone replacement therapy, women receive estrogen to treat menopause symptoms. Estrogen also thickens the lining of the uterus and can increase the risk of uterine cancer. Progesterone is administered in conjunction with estrogen to reduce this risk. Progesterone is available in various forms: tablets, capsules, injections, vaginal inserts and vaginal gel.  Progesterone is available under the names First Progesterone MC10, First Progesterone MC5, Crinone, Endometrin, Pro-Gest and Prometrium. Progesterone is also used to stimulate menstruation in women of childbearing age who are not menstruating regularly or at all. Progesterone can also be used in birth control and as an infertility treatment.

Progesterone together with estrogen prepares the lining of the uterus for implantation of a fertilized egg (embryo) and helps maintain early pregnancy. If pregnancy does not occur, levels of estrogen and progesterone drop, causing the uterine lining to shed.