What triggers the LH surge
What triggers the mid-cycle LH surge that causes ovulation?
Answer A: explanation for every choice
A
Correct. Estrogen from the dominant follicle normally inhibits LH, but sustained high levels flip to positive feedback and produce the surge.
B
Progesterone rises after ovulation, during the luteal phase.
C
Estrogen peaks just before the surge.
D
hCG appears only after implantation.
TakeawayHigh, sustained estrogen → positive feedback → LH surge → ovulation.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb139.