The luteal phase of the menstrual cycle occurs on which days?

• A. Cycle days 15-28
• B. Cycle days 5-13
• C. Cycle day 14
• D. Cycle days 7-14

Answer: (A)

The luteal phase is the post-ovulation window when the corpus luteum produces progesterone to support the endometrium in case of implantation. It begins after ovulation and lasts about 14 days, ending just before menstruation starts. In a typical 28-day cycle, ovulation occurs around day 14, so the luteal phase runs from day 15 through day 28. This differentiates it from the follicular phase (before ovulation, roughly days 1–13) and from the day of ovulation itself (around day 14). Therefore, the luteal phase corresponds to days 15 through 28.