USMLE Step 1 Practice Exam 2026 – Comprehensive All-in-One Guide for Exam Success!

Ovulation typically occurs around day 14 of a standard 28-day menstrual cycle, which is why the timeframe between days 14 and 16 is considered the correct answer. This phase, known as the luteinizing hormone surge, triggers the release of the ovum from the ovary.

In a typical menstrual cycle, the follicular phase leads up to ovulation, and this phase generally lasts about 14 days but can vary among individuals. Day 14 is the midpoint of the cycle for many, aligning with the ovulation period.

The other options represent timeframes that are either too early or too late in the cycle for ovulation to occur. For example, days 7 to 9 and 10 to 12 fall within the follicular phase before the ovulatory period, while days 19 to 21 fall within the luteal phase after ovulation has already occurred.