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 amenorrhea as follows:[1]
- Primary amenorrhea: lack of menses by age 15 years in a patient with appropriate development of secondary sexual characteristics, or lack of menses within 5 years of breast development if breast development occurred before age 10 years
- Secondary amenorrhea: lack of menses for >3 months in a nonpregnant female who previously had regular menstrual cycles, or lack of menses for 6 months in a female who previously had irregular menstrual cycles.
Although attributes overlap between the two groups, the diagnostic approaches vary significantly.
Contemporary population-level evidence regarding the incidence and prevalence of amenorrhea is scarce.
The prevalence of secondary amenorrhea is estimated to be 3% to 4%; primary amenorrhea is considerably less common (<0.1%).[2] [3] [4]
Prevalence of secondary amenorrhea appears to be higher among women who participate in physically demanding sports or disciplines, including cycling (56%), triathlon (40%), rhythmic gymnastics (31%), and ballet (20% to 23%).[5] [6] [7]
Common causes of secondary amenorrhea include polycystic ovary syndrome, hypothalamic dysfunction, premature ovarian insufficiency, and hyperprolactinemia.[1] [8] [9]
In general, amenorrhea accounts for a relatively small percentage of patient visits, even at highly specialized centers.
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 health outcomes of such patients. For example, in polycystic ovary syndrome and hyperinsulinemia, behavioral and dietary modifications may prevent subsequent cardiovascular disease.
