Progesterone is a hormone produced by the ovaries, the adrenal glands, and, during pregnancy it is produced by the placenta. Progesterone is responsible for the stimulation and regulation of several functions. It regulates the monthly menstrual cycle, prepares the body for conception, and plays a role in sexual desire. One of progesterone's biggest roles is to cause the endometrium to produce proteins in preparation for the implantation of a fertilized egg.
