A 24-year-old woman requests combined oral contraceptive pills for cycle regulation. She has no medical comorbidities. The primary mechanism by which COCPs prevent ovulation is through inhibition of which hormone surge?
- A FSH surge in the early follicular phase
- B Progesterone surge in the luteal phase
- C LH surge in the midcycle ✓
- D GnRH pulsatility throughout the cycle
Correct answer: C. LH surge in the midcycle
Explanation
The primary mechanism by which COCPs prevent ovulation is suppression of the midcycle LH surge through negative feedback on the anterior pituitary. The progestin component inhibits the LH surge, while the FSH suppression (which prevents follicular development) is a secondary mechanism. Without the LH surge, the dominant follicle cannot rupture, and ovulation is prevented.
Reference: Yen & Jaffe's Reproductive Endocrinology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.