Irregular menstruation

Irregular menstruation
Classification and external resources
Specialty	gynaecology
ICD-10	N92.1, N92.5, N92.6
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Irregular menstruation is a menstrual disorder whose manifestations include irregular cycle lengths as well as metrorrhagia (vaginal bleeding between expected periods).

Irregular cycles or irregular periods is an abnormal variation in length of menstrual cycles. A female usually experiences cycle length variations of up to eight days between the shortest and longest cycle lengths. Lengths ranging between eight and 20 days are considered moderately irregular. Variation of 21 days or more is considered very irregular.

Alternatively, a single menstruation period may be defined as irregular if it is shorter than 21 days or longer than 36 days. If they are regularly shorter than 21 days or longer than 36 (or 35) days, the condition is termed polymenorrhea or oligomenorrhea, respectively.

Other types of conditions that can be referred to by "irregular menstruation" include:

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