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Immunology & Autoimmune
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Luteinizing hormone (LH) is a hormone made by your pituitary gland that helps regulate the reproductive system. In women and people assigned female at birth, LH works with follicle stimulating hormone to support ovarian function and triggers ovulation.
In men and people assigned male at birth, LH stimulates the testes to produce testosterone. The test measures the amount of LH in your blood to show how well your pituitary gland and gonads are communicating.
LH testing is used to evaluate menstrual irregularities, trouble conceiving, suspected polycystic ovary syndrome, the menopausal transition, and possible pituitary problems. In males, it helps assess low testosterone symptoms, sexual dysfunction, or delayed development, and can help distinguish a testicular condition from a pituitary or hypothalamic cause. In children, it assists in evaluating early or delayed puberty.
Results can guide treatment choices and timing for fertility care and ovulation monitoring. Your clinician may pair LH with tests such as FSH, estradiol, testosterone, prolactin, and thyroid hormones to get a complete picture. A standard blood draw is the usual method, and risks are minimal.
Your provider will interpret LH in the context of your symptoms, medical history, physical exam, and related tests such as FSH, estradiol, testosterone, prolactin, and thyroid studies. In people who menstruate, LH naturally fluctuates during the cycle, with a brief surge near ovulation. During pregnancy, LH is typically suppressed, and after ovarian function ends it is often higher.
In males, a higher LH with low sex hormone levels may point to a primary problem in the testes, while a lower LH with low sex hormone levels can suggest a pituitary or hypothalamic issue. In children, patterns are viewed relative to pubertal stage and clinical signs.
If results do not match how you feel, your clinician may repeat testing, adjust the timing to your cycle, review medicines and supplements, or order additional studies. Do not start, stop, or change medications without medical advice.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
LH is released in pulses and varies across the menstrual cycle, so the day and timing of your sample can affect the result.
Pills, patches, rings, implants, injections, and hormone therapies can suppress LH and alter its usual patterns.
During pregnancy and shortly after delivery, LH is typically suppressed, which can influence interpretation.
After ovarian function ceases, LH levels are generally higher; knowing your stage helps your provider interpret results.
GnRH agonists or antagonists, clomiphene, anabolic steroids, opioids, and some psychiatric drugs can raise or lower LH.
High-dose biotin and rare antibody interferences can affect some immunoassays and may skew results.
Severe illness, significant stress, or intense training can transiently change the signaling between brain and gonads.
Improper handling or drawing at an atypical time may give misleading results; repeating the test can clarify outliers.
References