A midcycle LH surge will stimulate which series of events?

A midcycle LH surge will stimulate which series of events?

• A. An increase in FSH
• B. Ovulation
• C. Anovulation
• D. Amenorrhea

Answer: (B)

The midcycle LH surge is the trigger for ovulation. When estrogen from the growing follicle rises to a high level, it exerts positive feedback on the hypothalamus and pituitary, causing a sharp rise in LH. This surge prompts the dominant follicle to rupture, releasing the oocyte — the ovulation event. In the hours to days that follow, the remaining follicular cells luteinize to form the corpus luteum, which then secretes progesterone (and some estrogen) to support the secretory lining of the uterus. So the key sequence starting with the LH surge is ovulation followed by luteinization and progesterone production. An increase in FSH occurs earlier in the cycle and is not the defining effect of the midcycle LH surge, and anovulation or amenorrhea are not immediate outcomes of this surge.

The midcycle LH surge is the trigger for ovulation. When estrogen from the growing follicle rises to a high level, it exerts positive feedback on the hypothalamus and pituitary, causing a sharp rise in LH. This surge prompts the dominant follicle to rupture, releasing the oocyte — the ovulation event. In the hours to days that follow, the remaining follicular cells luteinize to form the corpus luteum, which then secretes progesterone (and some estrogen) to support the secretory lining of the uterus. So the key sequence starting with the LH surge is ovulation followed by luteinization and progesterone production. An increase in FSH occurs earlier in the cycle and is not the defining effect of the midcycle LH surge, and anovulation or amenorrhea are not immediate outcomes of this surge.