During menopause, the levels of the ovarian hormone called inhibin begin to decrease, causing a decrease in the production of the FSH hormone. As the inhibin levels fall, FSH levels increase over the menopausal transition period.
FSH levels are responsible for estrogen levels rising during menopause, so as the FSH levels fluctuate throughout menopause, so do estrogen levels, according to the American Society for Reproductive Medicine.
During menopause, estrogen levels can spike to high levels when there is a higher stimulation of FSH hormones in the body. Once the ovaries lose their ability to produce hormones, estrogen levels begin to drop, regardless of the high levels of FSH.
Progesterone, a hormone that is generally produced in high levels after ovulation, begins to decrease during the menopausal transition for some women. However, since no two women are the same, there is no specific blood test that can be conducted to predict the onset of menopause.
Hormone tests are not a precise tool for diagnosing menopause due to the fluctuation of hormone levels throughout the menopause transition as well as the menstrual cycle, according to the Menopause website. Saliva testing is a method some clinicians recommend, but the tests are often inaccurate and are expensive.
FSH levels are tested to confirm menopause. Results showing an elevated level of 30 mIU/mL or higher with a female not having a menstrual cycle for a year is a sound cause for diagnosing a woman with menopause.