Hormonal measurements can determine if a woman is still fertile, or if she is menopausal. To determine if a woman is in menopause, two hormone levels are usually checked: FSH and estradiol. FSH, or follicular stimulating hormone, is produced by the pituitary gland in response to low levels of estrogen during the menstrual cycle. FSH stimulates the growth of an ovarian follicle which produces an ovum, or egg. As a women ages, the number of eggs in her ovaries decline, until they are very few left. The pituitary gland must work harder to encourage the ovary to ovulate, so the FSH gets higher. An elevated FSH signifies menopause.
Doctors also measure estradiol levels. Estradiol is the hormone that is produced by the ovarian follicle during ovulation. Estrogen gives us our female characteristics, and is necessary to grow the endometrial lining to prepare for conception and implantation of the fertilized egg. In menopause, the estradiol levels declines to very low levels. Therefore, an elevated FSH and low estradiol signifies menopause. Sometimes, the FHS is elevated and the estradiol level is till high. This means that there are still some functional ovarian follicles. If follicles remain, ovulation can occur, and usually estrogen levels are variable.