From the Guidelines
FSH and LH hormone levels should be interpreted based on the most recent and highest quality evidence, which suggests that normal FSH levels in premenopausal women range from 4-13 mIU/mL during the follicular phase, and LH levels range from 1-18 mIU/mL during the follicular phase, with abnormal levels indicating conditions like polycystic ovary syndrome or testicular dysfunction 1.
FSH and LH Hormone Levels
FSH (follicle-stimulating hormone) and LH (luteinizing hormone) are reproductive hormones produced by the pituitary gland.
- Normal FSH levels in premenopausal women range from 4-13 mIU/mL during the follicular phase, 5-22 mIU/mL at mid-cycle, and 2-13 mIU/mL during the luteal phase.
- For men, normal FSH levels are typically 1.5-12.4 mIU/mL.
- LH levels in premenopausal women range from 1-18 mIU/mL during the follicular phase, 24-105 mIU/mL at mid-cycle, and 0.4-20 mIU/mL during the luteal phase.
- In men, normal LH levels are approximately 1.8-8.6 mIU/mL. These hormones are crucial for reproduction, with FSH stimulating egg and sperm development and LH triggering ovulation in women and testosterone production in men.
Abnormal FSH and LH Levels
Abnormal levels can indicate conditions like menopause, primary ovarian insufficiency, polycystic ovary syndrome, or testicular dysfunction.
- A study published in the Journal of Neurology, Neurosurgery and Psychiatry found that FSH levels >35 IU/l and LH levels >11 IU/l can indicate reproductive endocrine disorders in women with epilepsy 1.
- Another study published in Nature Reviews Endocrinology found that elevated serum IGF1 levels can be a reliable marker for GH excess, but marginal or mild elevation in adolescence needs cautious interpretation 1. Testing typically involves a blood sample, and interpretation should always be done by a healthcare provider who can consider individual factors and other relevant tests.
Clinical Significance
The clinical significance of FSH and LH hormone levels lies in their ability to indicate reproductive disorders and guide treatment decisions.
- Abnormal FSH and LH levels can indicate polycystic ovary syndrome (PCOS), a common cause of irregular periods in women.
- PCOS is a form of hyperandrogenic chronic anovulation, and abnormal FSH and LH levels can help diagnose and manage the condition 1.
- In men, abnormal FSH and LH levels can indicate testicular dysfunction or other reproductive disorders. Overall, FSH and LH hormone levels are essential for diagnosing and managing reproductive disorders, and their interpretation should be based on the most recent and highest quality evidence.
From the Research
FSH and LH Hormone Levels
- FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone) are essential hormones in the reproductive system, playing crucial roles in follicle development and ovulation 2.
- The levels of FSH and LH can vary depending on the menstrual cycle and age of the individual 3.
- In normal women, FSH levels increase with age, while LH levels may decrease 3.
- The FSH:LH ratio can also be used as a predictor of ovarian reserve and reproductive age 3.
- Abnormal levels of FSH and LH can be associated with various reproductive disorders, such as polycystic ovary syndrome (PCOS) 4, 5.
PCOS and Hormone Levels
- In PCOS patients, LH levels are often elevated, while FSH levels are decreased, resulting in an increased LH:FSH ratio 4, 5.
- The LH:FSH ratio can be used as a diagnostic criterion for PCOS, with a ratio greater than 1.23 being indicative of PCOS 5.
- Other hormonal parameters, such as anti-Mullerian hormone (AMH), free androgen index (FAI), and testosterone, can also be altered in PCOS patients 5.
Factors Affecting FSH and LH Action
- Reduced FSH and LH action can be caused by various factors, including molecular characteristics, signaling, aging, and polymorphisms 2.
- These factors can lead to diminished gonadotropin action, resulting in reduced fertility and resistance to ovarian stimulation 2.
- The importance of FSH and LH action has been highlighted by the International Committee for Monitoring Assisted Reproduction Technologies (ICMART) in their definition of hypogonadotropic hypogonadism 2.