PROGESTERONE IS A FEMALE HORMONE PRODUCED BY THE OVARIES DURING RELEASE OF A MATURE EGG FROM AN OVARY (OVULATION). THIS TEST IS VERY HELPFUL IN DETERMINING THE CAUSE OF INFERTILITY, TRACK OVULATION, HELP DIAGNOSE AN ECTOPIC OR FAILING PREGNANCY, MONITOR THE HEALTH OF A PREGNANCY, AND HELP DIAGNOSE THE CAUSE OF ABNORMAL UTERINE BLEEDING. IN A PREGNANCY IF THE EGG IS NOT FERTILIZED PROGESTERONE LEVEL DROP AND MENSTRUAL BEGINS. PROGESTERONE IS A STEROID HORMONE WHOSE MAIN ROLE IS TO HELP PREPARE A WOMEN'S BODY FOR PREGNANCY, ALSO WORKS IN CONJUNCTION WITH SEVERAL OTHER FEMALE HORMONES.