Normal follical stimulating hormone levels in menopausal and postmenopausal women are between 25.8 and 134.8, according to MedlinePlus. FSH is produced by the pituitary gland in the brain and regulates the female menstruation cycle. An FSH blood test is commonly used to diagnose menopause and infertility.
When a woman enters perimenopause, her follicle stimulating hormone level increases and remains increased after she is postmenopausal. The perimenopausal stage can last up to eight to 10 years. A woman enters menopause when her last monthly menstrual cycle stops, and she is considered to be postmenopausal when she has not had a menstrual cycle for at least one year, as reported by Cleveland Clinic.