Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.
The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.
Updates regarding government operating status and resumption of normal operations can be found at OPM.gov.
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
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.
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.
Master-Hunter, T., & Heiman, D. L. (2006). Amenorrhea: Evaluation and treatment. American Family Physician, 73, 1374–1382.
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.
Apgar, B. S., Kaufman, A. H., George-Nwogu, U., & Kittendorf, A. (2007). Treatment of menorrhagia. American Family Physician, 75, 1813–1819.
French, L. (2005). Dysmenorrhea. American Family Physician, 71, 285–291.