Irregular menstruation

Classification and external resources
ICD-10	N92.1, N92.5, N92.6

Irregular menstruation (or irregular cycles/periods) is an abnormal variation in length of menstrual cycles in a woman. Normally, it is actually unusual for a woman to experience cycle length variations of less than four days between the shortest and longest cycle lengths.^[1] However, length variation between eight and 20 days is considered as moderately irregular cycles.^[1] Variation of 21 days or more is considered very irregular.^[1] Alternatively, an irregular menstruation period may be defined as one shorter than 21 days, or longer than 36 days.^[2]

Types

The term metrorrhagia is often used for irregular menstruation that occurs between the expected menstrual periods.^[3]

Oligomenorrhea is infrequent or very light menstruation,^[4] Also, menstrual periods should have been regularly established previously before the development of infrequent flow.^[4] and often (but not always) involves irregular intervals.

References

1. ^ ^{a b c} Kippley, John; Sheila Kippley (1996). The Art of Natural Family Planning (4th ed.). Cincinnati, OH: The Couple to Couple League. pp. 92. ISBN 0-926412-13-2. 
2. ^ about.com > If I Have Irregular Periods, Will I Have Trouble Getting Pregnant? By Rachel Gurevich. Updated October 26, 2009
3. ^ MedicineNet.com > Definition of Metrorrhagia Last Editorial Review: 3/17/2003
4. ^ ^{a b} thefreedictionary.com > oligomenorrhea This dictionary, in turn, is citing: Gale Encyclopedia of Medicine. 2008