Which term describes a menstrual cycle interval of less than 21 days?

• A. Polymenorrhea
• B. Oligomenorrhea
• C. Metrorrhagia
• D. Dysmenorrhea

Answer: (A)

Polymenorrhea describes menstrual cycles that occur more frequently than every 21 days. In other words, the cycle interval is shorter than the lower limit of the normal 21–35 day range. This distinction helps separate regular variability from a pattern of rapid cycling. Oligomenorrhea refers to cycles that are infrequent and spaced more than 35 days apart. Metrorrhagia means bleeding that occurs at irregular intervals between expected menses, and dysmenorrhea denotes painful cramps during menstruation. If cycles are consistently under 21 days, it’s worth evaluating for hormonal imbalances or other underlying conditions that can shorten cycle length.