Which single investigation best confirms that a woman with regular cycles is ovulating?

• A Serum estradiol on day 12 of the cycle
• B Mid-luteal serum progesterone measured 7 days before expected menses ✓
• C LH surge detection on daily urinary testing throughout the cycle
• D Basal body temperature charting over one cycle

Explanation

A mid-luteal progesterone above 3 ng/mL confirms a functional corpus luteum and hence recent ovulation; many laboratories use higher thresholds such as 10 ng/mL as evidence of good luteal function. Day 12 estradiol reflects follicular growth only. Urinary LH kits detect the preovulatory surge but miss some cycles and confirm the surge rather than completed ovulation. BBT charting is subjective and far less reliable.

Reference: Williams Gynecology, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.