Amenorrhea is the transient or permanent absence of menstrual flow. There is no consensus on the definition of amenorrhea, but it may be subdivided into primary and secondary presentations relative to menarche as follows:[1]Practice Committee of the American Society for Reproductive Medicine. Current evaluation of amenorrhea. Fertil Steril. 2008 Nov;90(suppl 5):S219-25.
https://www.fertstert.org/article/S0015-0282(08)03527-9/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/19007635?tool=bestpractice.com
Primary amenorrhea: lack of menses by age 15 years in a patient with appropriate development of secondary sexual characteristics, or absent menses by age 13 years and no other pubertal maturation
Secondary amenorrhea: lack of menses in a nonpregnant female for at least 3 cycles of her previous interval, or lack of menses for 6 months in a patient who was previously menstruating.
Although attributes overlap between the two groups, the diagnostic approaches vary significantly.
Evidence of the current prevalence of amenorrhea is scarce. Data from the 1990s suggest that about 3% in women who have previously had regular menstrual periods had amenorrhea. The prevalence appears to be higher in college students (3% to 5%), competitive endurance athletes (5% to 60%), and ballet dancers (19% to 44%).[1]Practice Committee of the American Society for Reproductive Medicine. Current evaluation of amenorrhea. Fertil Steril. 2008 Nov;90(suppl 5):S219-25.
https://www.fertstert.org/article/S0015-0282(08)03527-9/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/19007635?tool=bestpractice.com
[2]Gordon CM, Ackerman KE, Berga SL, et al. Functional hypothalamic amenorrhea: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2017 May 1;102(5):1413-39.
https://academic.oup.com/jcem/article/102/5/1413/3077281?login=false
http://www.ncbi.nlm.nih.gov/pubmed/28368518?tool=bestpractice.com
The prevalence of primary amenorrhea in the US is <0.1%, compared with 3% to 4% for secondary amenorrhea.[1]Practice Committee of the American Society for Reproductive Medicine. Current evaluation of amenorrhea. Fertil Steril. 2008 Nov;90(suppl 5):S219-25.
https://www.fertstert.org/article/S0015-0282(08)03527-9/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/19007635?tool=bestpractice.com
[2]Gordon CM, Ackerman KE, Berga SL, et al. Functional hypothalamic amenorrhea: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2017 May 1;102(5):1413-39.
https://academic.oup.com/jcem/article/102/5/1413/3077281?login=false
http://www.ncbi.nlm.nih.gov/pubmed/28368518?tool=bestpractice.com
[3]Timmreck LS, Reindollar RH. Contemporary issues in primary amenorrhea. Obstet Gynecol Clin North Am. 2003 Jun;30(2):287-302.
http://www.ncbi.nlm.nih.gov/pubmed/12836721?tool=bestpractice.com
[4]Pettersson F, Fries H, Nillius SJ. Epidemiology of secondary amenorrhea: incidence and prevalence rates. Am J Obstet Gynecol. 1973 Sep 1;117(1):80-6.
http://www.ncbi.nlm.nih.gov/pubmed/4722382?tool=bestpractice.com
The most common causes include polycystic ovary syndrome, hypothalamic dysfunction, premature ovarian failure, and hyperprolactinemia.[5]Polycystic ovary syndrome and secondary amenorrhoea. In: Edmonds K, ed. Dewhurst's textbook of obstetrics and gynaecology. 9th edition. Chichester: Wiley-Blackwell; 2018:513-33.
Although there are many causes of secondary amenorrhea, the incidence of each etiology is low. In general, amenorrhea accounts for a relatively small percentage of patient visits, even at highly specialized centers.
Despite the low prevalence of secondary amenorrhea, a prompt, comprehensive assessment is warranted unless the patient is pregnant, lactating, or using hormonal contraceptives, as amenorrhea is often the presenting sign of an underlying reproductive disorder. A delay in diagnosis and treatment may adversely impact the future of such patients. For example, in polycystic ovary syndrome and hyperinsulinemia, behavioral and dietary modifications may prevent subsequent cardiovascular disease.