When does the LH surge occur relative to estradiol levels?

When does the LH surge occur relative to estradiol levels?

• A. Before estradiol peaks
• B. After estradiol peaks
• C. Simultaneously with estradiol peak
• D. Independent of estradiol

Answer: (B)

The LH surge happens after estradiol peaks because sustained high levels of estradiol switch the feedback on the hypothalamic-pituitary axis from negative to positive. When estradiol remains elevated for a critical period, it prompts a rapid, large release of GnRH and, in turn, a spike of LH from the anterior pituitary. This LH surge occurs once estradiol has peaked and is what triggers ovulation, with progesterone rising afterward from the newly formed corpus luteum.

The LH surge happens after estradiol peaks because sustained high levels of estradiol switch the feedback on the hypothalamic-pituitary axis from negative to positive. When estradiol remains elevated for a critical period, it prompts a rapid, large release of GnRH and, in turn, a spike of LH from the anterior pituitary. This LH surge occurs once estradiol has peaked and is what triggers ovulation, with progesterone rising afterward from the newly formed corpus luteum.