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Evaluation and management of a patient with amenorrhea is common in gynecology, and the prevalence of pathologic amenorrhea ranges from 3 to 4 percent in reproductive-aged populations (Bachmann, 1982). Amenorrhea has classically been defined as primary (no prior menses) or secondary (cessation of menses). Although this distinction does suggest a relative likelihood of finding a particular diagnosis, the approach to diagnosis and treatment is similar for either presentation (Tables 17-1 and 17-2). Of course, amenorrhea is a normal state prior to puberty, during pregnancy and lactation, and following menopause. Evaluation is considered for an adolescent: (1) who has not menstruated by age 15 or within 3 years of thelarche or (2) has not menstruated by age 14 and shows signs of hirsutism, excessive exercise, or eating disorder (American College of Obstetrician and Gynecologists, 2017d). Secondary amenorrhea for 3 months or fewer than nine cycles per year also is investigated (American Society for Reproductive Medicine, 2008; Klein, 2013). In some circumstances, testing reasonably may be initiated despite the absence of these strict criteria. Examples include a patient with the stigmata of Turner syndrome, obvious virilization, or a history of uterine curettage. An evaluation for delayed puberty is also considered before the ages listed above if the patient or her parents are concerned.
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NORMAL MENSTRUAL CYCLE
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A differential diagnosis for amenorrhea can be constructed based on requirements for normal menses. Ovarian function in ...