Follicle-stimulating hormone (FSH) is a hormone produced by the pituitary gland in the brain that stimulates the growth of follicles in the ovaries in women. In general, as a woman approaches menopause, her ovarian function declines, leading to higher FSH levels.
The normal range for FSH in women still in their reproductive years is typically between 5 and 25 IU/L, depending on the stage of their menstrual cycle. During perimenopause, which is the transitional period before menopause, these levels can begin to rise significantly.
While there’s no universally agreed-upon level that signifies perimenopause, FSH levels that consistently measure over 25 to 30 IU/L could suggest that a woman is in this transition phase. However, FSH levels can fluctuate greatly during perimenopause, and a single measurement might not be enough for a definitive diagnosis. Some women might experience FSH levels far higher, even over 50 IU/L during this period.
Remember that every individual is unique and these values can vary. Therefore, interpretation of FSH levels and diagnosis of perimenopause should be done by a healthcare provider who can consider the full context of the individual’s health situation and symptoms. Always consult with a healthcare provider for any medical concerns or questions.