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Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein.

Luteinizing Hormone (LH)

Luteinizing hormone (LH) is produced by the pituitary gland. In women, LH helps regulate the menstrual cycle and egg production (ovulation); in men, LH stimulates the production of testosterone, which plays a role in sperm production.

Women's LH levels normally vary with the phase of the menstrual cycle, rapidly increasing just before ovulation occurs. This "LH surge" is a dependable sign that a woman is in a fertile time of her cycle. Men's LH levels normally remain constant.

Abnormally high or low LH levels can be a sign of an inability to produce eggs or sperm.