FSH, or follicular stimulating hormone, is a measure of the pituitary gland signaling the ovary to recruit an egg for ovulation. When a woman is closer to menopause, the pituitary works harder to find the eggs remaining in the ovary that are ovulated, and FSH levels increase. FSH is often measured on the third day of the menstrual cycle, and it is an indicator of fertility. A level of <10mIU/mL signifies good ovarian reserve and fertility. Levels in the range of 10-15 mIU/mL are borderline. When the FSH is in this level, there is a decrease in pregnancy and live birth rates. Estradiol levels are also checked on day #3. Levels >80 pg/mL are concerning for decreased ovarian reserve. Antimuellerian hormone (AMH) is now often used to monitor ovarian reserve. Scientists have found that AMH drops significantly during the reproductive years, and drops to zero by age 50. A level greater the 0.5 ng/mL signifies good ovarian reserve. If the level is very low, <.15 ng/mL, it is not likely that a women will respond to ovarian stimulatory drugs used for infertility. This is one test that does not depend on the the time during the menstrual cycle that it is checked. There are studies that use the AMH to predict the age of menopause. Antral follicle count uses sonography to measure developing follicles or eggs in the ovary. The count is done on day 2-4 of thy cycle, with day 1 being the first day of menstrual flow. An antral follicle count of 3-10 indicates decreased ovarian reserve.