What hormone surge is primarily responsible for triggering ovulation?

The surge in luteinizing hormone (LH) is the critical event that triggers ovulation in the menstrual cycle. Prior to ovulation, the follicle in the ovary matures under the influence of various hormones, including follicle-stimulating hormone (FSH) and estrogen. As the dominant follicle develops, it produces high levels of estrogen, which leads to a feedback mechanism that stimulates a rapid increase in LH released from the anterior pituitary gland.

This LH surge is pivotal as it causes the final maturation of the ovarian follicle and leads to the release of the egg from the ovary. Typically, this surge occurs around the middle of the menstrual cycle, marking the transition from the follicular phase to the luteal phase. Therefore, the role of LH in triggering ovulation makes it the primary hormone associated with this process.