Between days 2-4 of your menstrual cycle, Dr. Allen may order preliminary bloodwork to be drawn to check the levels of FSH and E2. These two hormones provide information about the communication between the brain and ovaries and are one of the tests used to determine ovarian reserve. The brain produces FSH that dries the cohort of follicles to compete for one to become the dominant follicle. As the dominant follicle grows it produces estradiol that feeds back to the brain.
