The progesterone test measures the amount of the female hormone progesterone in the blood. Progesterone is produced when a woman’s ovaries release a mature egg during ovulation. Progesterone helps the lining of the uterus receive the egg if it becomes fertilized. If the egg is not fertilized, the level of progesterone drops and menstruation begins. During pregnancy a woman’s body produces a high level of progesterone (about 10 times higher).
The progesterone blood test is used to monitor fertility therapies, help find the cause of infertility, assess the risk of miscarriage, and detect problems with the adrenal glands and some types of cancer.