Progesterone is a hormone produced in the ovaries during the second
half of the menstrual cycle that helps prepare the uterus for pregnancy.
Progesterone is also produced by the placenta during pregnancy and helps the
placenta function properly.
At the end of pregnancy, a drop in progesterone helps start labor
When a woman reaches the end of her reproductive years and begins
menopause, her level of progesterone declines.