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What does luteinizing hormone do during the menstrual cycle?

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Diagram of the menstrual cycle showing hormone levels, follicle development, and endometrial changes across 28 days. It highlights menstruation, ovulation, and the follicular and luteal phases, with labeled curves for estrogen, progesterone, FSH, and LH. — menstruation Cyclical changes during a woman's normal ovulatory menstrual cycle.

Luteinizing hormone (LH) is a gonadotropic hormone produced by the pituitary gland that plays a critical role in the female reproductive cycle. Its primary functions during the menstrual cycle include:1

Triggering Ovulation: A sudden peak release of LH from the pituitary gland stimulates the release of an egg from the ovary, an event that typically occurs around the middle of the monthly cycle.23
Formation of the Corpus Luteum: Following ovulation, LH promotes the transformation of the ruptured ovarian follicle into the corpus luteum.13
Hormone Secretion: The resulting corpus luteum acts as an endocrine gland that secretes progesterone and estrogens. Progesterone is essential for preparing the uterus for the potential implantation of a fertilized egg.143

If fertilization does not occur, the corpus luteum becomes inactive, leading to a drop in hormone levels and the onset of menstruation.43