Question

About which day in a normal human menstrual cycle does rapid secretion of $LH$ (popularly called $LH$ surge) normally occurs?

• A. $14,^{th}$day
• B. $20^{th}$ day
• C. $5^{th}$ day
• D. $11^{th}$ day

Answer 1

Answer: (A)

$14,^{th}$day

Answer 2

The hormone estradiol suppresses the secretion of luteinizing hormone (LH) during the follicular phase. When the egg has almost matured, the levels of estradiol becomes maximum and beyond the optimum level, this effect is reversed and estrogen stimulates the production of large amounts of LH. This process is known as LH-surge and it starts around day $13^{\text {th }}$ of the average 28 - day cycle and may last for 24 - 48 hours