Follicle-stimulating hormone (FSH) is produced in the pituitary gland and has direct effects on ovaries, testes, and reproduction. Low levels in women are associated with menstrual irregularities, caloric deficit, and pituitary or hypothalamic dysfunction, while elevated levels may be associated with ovarian insufficiency and pesticide exposure.
Amenorrhea can be associated with lower FSH in the case of hypothalamic or pituitary dysfunction and higher FSH in the event of ovarian insufficiency.
Standard Ranges (Immunoassay)
Low FSH in females may be seen with amenorrhea due to hypothalamic or pituitary dysfunction, caloric deficit, and hypothalamic or anterior pituitary dysfunction (Orlowski 2021).
High FSH is associated with pituitary adenoma, ovarian failure, early menopause, Turner syndrome, and the type of amenorrhea associated with ovarian insufficiency (Orlowski 2021). An elevated FSH may be associated with pesticide exposure (Lambertino 2021).
Follicle-stimulating hormone is a glycoprotein produced by the pituitary that has effects on the ovaries and testes. Both FSH and LH can be assessed to evaluate infertility. Levels in the blood increase significantly and then fall by the 10th day of the menstrual cycle. Failure to decline indicates poor ovarian reserve and decreased likelihood of pregnancy (Pagana 2021).
In women, FSH regulates follicular development and stimulates aromatase which converts androgens to estradiol. In PCOS there is an increased ratio of LH to FSH which leads to an androgen excess due to a relative insufficiency of aromatase (Orlowski 2021). FSH levels increase with age and the transition into menopause. However, levels of FSH alone are insufficient for identifying menopause (Henrich 2006).
Henrich, Janet B et al. “Limitations of follicle-stimulating hormone in assessing menopause status: findings from the National Health and Nutrition Examination Survey (NHANES 1999-2000)*.” Menopause (New York, N.Y.) vol. 13,2 (2006): 171-7. doi:10.1097/01.gme.0000198489.49618.96
Lambertino, Anissa et al. “Associations of PCBS, dioxins and furans with follicle-stimulating hormone and luteinizing hormone in postmenopausal women: National Health and Nutrition Examination Survey 1999-2002.” Chemosphere vol. 262 (2021): 128309. doi:10.1016/j.chemosphere.2020.128309
Orlowski, Michelle. and Manbeer S. Sarao. “Physiology, Follicle Stimulating Hormone.” StatPearls, StatPearls Publishing, 9 May 2021.
Pagana, Kathleen Deska, et al. Mosby's Diagnostic and Laboratory Test Reference. 15th ed., Mosby, 2021.