Follicle stimulating hormone is typically measured on day three of a woman's cycle when the levels of estradiol (E2) and progesterone are at the lowest point of the menstrual cycle.
Follicle stimulating hormone is typically measured in the early follicular phase of the menstrual cycle, typically day three to five, counted from last menstruation. At this time, the levels of estradiol (E2) and progesterone are at the lowest point of the menstrual cycle.