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Abnormal uterine bleeding is an overarching term that is defined as bleeding from the uterine corpus that is irregular in volume, frequency, or duration in absence of pregnancy (Table 96-1).1,2 Vaginal bleeding is a common complaint in the ED, and differential diagnoses include pregnancy, structural abnormalities (e.g., polyps, fibroids), endometritis, coagulopathies, trauma, and various other causes. This chapter will focus on the ED evaluation and management of abnormal uterine bleeding.
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A normal menstrual cycle has an average duration of 4.5 to 8 days and an interval of 24 to 38 days between the onset of menses. The average blood loss is ≤30 mL, and menstrual blood loss >80 mL is considered abnormal. Menstrual cycle variation during early menarche and the perimenopausal period is due to high prevalence of anovulation. Figure 96-1 depicts hormonal and endometrial changes associated with a normal menstrual cycle.
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In response to the rising estrogen levels, the pituitary gland secretes follicle-stimulating hormone and luteinizing hormone, stimulating the release of a mature oocyte. The residual follicular capsule forms the corpus luteum. During the luteal phase, the corpus luteum secretes estrogen and progesterone, which maintains the integrity of the endometrium for implantation. In the absence of human chorionic gonadotropin released by a pregnancy, the corpus luteum involutes, and ...