Definition: Bleeding intervals shorter than 21 days. This anomaly is quite frequent in puberty and adolescence and is caused by hormonal imbalance within an unstable cycle. There may be an estrogen deficit in an anovulatory cycle or a short corpus luteum phase. Polymenorrhea is usually transient and self-limited. Treatment is indicated if it persists or is disturbing or if blood loss is considerable. Treatment mainstays are progestagens in the second phase of the cycle (

table 3) or an oral contraceptive.