What are menstrual irregularities?

For most women, a normal menstrual cycle ranges from 21 to 35 days.1 However, 14% to 25% of women have irregular menstrual cycles, meaning the cycles are shorter or longer than normal; are heavier or lighter than normal; or are experienced with other problems, like abdominal cramps.2 Irregular cycles can be ovulatory, meaning that ovulation occurs, or anovulatory, meaning ovulation does not occur.

The most common menstrual irregularities include:

  • Amenorrhea (pronounced ey-men-uh-REE-uh) or absent menstrual periods:3,4,5,6 When a woman does not get her period by age 16, or when she stops getting her period for at least 3 months and is not pregnant.
  • Oligomenorrhea (pronounced ol-i-goh-men-uh-REE-uh) or infrequent menstrual periods: Periods that occur more than 35 days apart.4
  • Menorrhagia (pronounced men-uh-REY-jee-uh) or heavy menstrual periods:3,4,7 Also called excessive bleeding. Although anovulatory bleeding and menorrhagia are sometimes grouped together, they do not have the same cause and require different diagnostic testing.7
  • Prolonged menstrual bleeding: Bleeding that exceeds 8 days in duration on a regular basis.4
  • Dysmenorrhea (pronounced dis-men-uh-REE-uh): Painful periods that may include severe menstrual cramps.8

Additional menstrual irregularities include:

  • Polymenorrhea (pronounced pol-ee-men-uh-REE-uh): Frequent menstrual periods occurring less than 21 days apart4
  • Irregular menstrual periods with a cycle-to-cycle variation of more than 20 days4
  • Shortened menstrual bleeding of less than 2 days in duration4
  • Intermenstrual bleeding: Episodes of bleeding that occur between periods, also known as spotting4


  1. American College of Obstetricians and Gynecologists (ACOG). (2012). FAQ: Abnormal uterine bleeding. Retrieved on May 24, 2016, from http://www.acog.org/Patients/FAQs/Abnormal-Uterine-Bleeding external link (PDF 464 KB)
  2. Whitaker, L., & Critchley, H. O. D. (2016). Abnormal uterine bleeding. Best Practice & Research Clinical Obstetrics & Gynaecology, 34, 54–65. Retrieved June 23, 2016, from http://www.sciencedirect.com/science/article/pii/S1521693415002266 external link
  3. Sweet, M. G., Schmidt-Dalton, T. A., Weiss, P. M., & Madsen, K. P. (2012). Evaluation and management of abnormal uterine bleeding in premenopausal women. American Family Physician, 85, 35–43.
  4. Munro, M. G., Critchley, H. O., & Fraser, I. S. (2012). The FIGO systems for nomenclature and classification of causes of abnormal uterine bleeding in the reproductive years: Who needs them? American Journal of Obstetrics and Gynecology, 207(4), 259–265.
  5. Master-Hunter, T., & Heiman, D. L. (2006). Amenorrhea: Evaluation and treatment. American Family Physician, 73, 1374–1382.
  6. Practice Committee of the American Society for Reproductive Medicine. (2008). Current evaluation of amenorrhea. Fertility and Sterility, 90, S219–S225. doi:10.1016/j.fertnstert.2008.08.038.
  7. Apgar, B. S., Kaufman, A. H., George-Nwogu, U., & Kittendorf, A. (2007). Treatment of menorrhagia. American Family Physician, 75, 1813–1819.
  8. French, L. (2005). Dysmenorrhea. American Family Physician, 71, 285–291.
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