Abnormal Menstrual Bleeding: Oligomenorrhea
A normal menstrual cycle is the end result of a sequence of purposeful and coordinated events that require an intact hypothalamic-pituitary-ovarian, uterine, and genital outflow tract axis. Any derailment along this compartmental axis can lead to an abnormal menstrual cycle. Infrequent menstrual bleeding, oligomenorrhea, or absent menstrual bleeding, amenorrhea, are common complaints in reproductive-aged women. Amenorrhea, or the absence of menses, is defined as primary if no prior menses have occurred and secondary if cessation of prior menses occurs. A thorough understanding of the spectrum of etiologies that can affect each of these compartments will allow the clinician to systematically evaluate a patient with oligomenorrhea and to identify the source of the menstrual dysfunction. In this chapter, we review the definitions and classifications of oligomenorrhea and amenorrhea as well as the common causes, diagnostic work-up, and management considerations involved. This review contains 5 figures, 4 tables, and 19 references. Key Words: amenorrhea, eating disorders, gonadal dysgenesis, hyperprolactinemia, hypogonadal, hypothyroidism, intrauterine adhesions, müllerian agenesis, primary ovarian insufficiency, Turner syndrome