Bleeding per vagina may occur at any point during the course of pregnancy and always warrants careful attention to identification and management of the underlying etiology. Bleeding that occurs early in pregnancy (generally within the first trimester) is covered in Chap. 9. Bleeding that occurs later in pregnancy (generally within the third trimester) is of particular concern because of the potentially serious underlying etiologies and the possibility of significant morbidity that exists for both the mother and the infant. A careful review of common etiologies combined with a careful history, directed physical examination, and selected diagnostic studies will allow the provider to identify the underlying cause and initiate appropriate management in a timely manner.

Late-pregnancy bleeding per vagina is a relatively common presentation. Approximately 5 % of all pregnancies is complicated by such bleeding. Although the differential diagnosis includes several disparate conditions, placental abnormalities comprise the majority of such bleeding (see Table 10.1). Half of all third-trimester bleeding is caused by either placental abruption or placenta previa. Other causes include cervical cytopathology, polyps, and “bloody show.” Bloody show refers to limited bleeding per vagina just prior to or at the onset of labor. Such bleeding is a variant of normal, although patients may require evaluation for other causes of bleeding.