Q&A: Diagnosing Cause of Vaginal Bleeding in Pregnancy

Bleeding from the vagina is a common event at all stages of pregnancy. The source is virtually always maternal, rather than fetal. Bleeding usually results from disruption of blood vessels in the decidua (ie, pregnancy endometrium) or from discrete cervical or vaginal lesions. The clinician typically makes a provisional clinical diagnosis based upon the patient's gestational age and the character of her bleeding (light or heavy, associated with pain or painless, intermittent or constant). Laboratory and imaging tests are then used to confirm or revise the initial diagnosis.

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This is a Question & Answer revision article designed for medical students and professionals preparing for the PLAB, MRCP or USMLE examinations. They are based on actual questions from these examinations. You may find the Women's Health article more useful, or one of our many articles on Diseases & Conditions, Medical Syndromes, Health & Wellness or Home Remedies.

In this article:
Urgent cases of vaginal bleeding in pregnancy
MCQ: clinical scenario
MCQ: answer
MCQ: explanation

Urgent cases of vaginal bleeding in pregnancy

The timing and setting of the evaluation of bleeding depend upon the severity. It is important to determine whether the patient is hemodynamically unstable so that supportive measures and treatment can be rapidly initiated in an appropriate setting (eg, emergency department, labor unit). Although orthostatic changes in blood pressure or pulse suggest severe blood loss requiring supportive care and rapid treatment, occasionally, young pregnant women can have massive bleeding without demonstrating tachycardia or hypotension. Careful assessment is important to avoid unnecessary delay in the management of such patients.

Hemoglobin/hematocrit, coagulation studies, and type and crossmatch should be obtained in all women who are hemodynamically unstable (hypotension, tachycardia, orthostasis, syncope).

The fetal heart rate should be checked and continuously monitored if delivery would be considered because of an abnormal fetal heart rate.

MCQ: clinical scenario

A primigravida has a single episode of vaginal bleeding in her third trimester. All investigations are normal and at term she goes on to have an uneventful normal vaginal delivery of a healthy infant. Placental examination post-delivery demonstrates a normal sized placenta with a dark-red mass lesion on the fetal surface.

The likely diagnosis is:

a) placental migration
b) uterine myoma
c) Uterine rupture
d) choriocarcinoma
e) chorangioma
f) vasa previa
g) subplacental abruptio placenta
h) subchorionic abruptio placenta
i) placenta accreta
j) placenta previa

MCQ: answer

The correct answer is E

MCQ: explanation

This appearance is most typical of a benign neoplasm composed of small vascular channels--essentially a form of hemangioma known as a chorangioma (chorioangioma, placental angioma). These are focal fleshy, dark-red areas on the placenta. These benign hemangiomas occur in 1 percent of placentas. While small chorioangiomas are usually of no clinical significance, large chorioangiomas are associated with fetal anemia, thrombocytopenia, hydrops, hydramnios, intrauterine growth retardation, prematurity and stillbirth. The neoplasm's gross appearance can be variable, with a tan to yellow to white to red to brown appearance depending upon vascularity, fibrosis, and hemosiderin deposition. Most chorangiomas are small and of no clinical significance.

Reference(s)
1). UpToDate: Overview of the etiology and evaluation of vaginal bleeding in pregnant women. Available online: https://www.uptodate.com/contents/overview-of-the-etiology-and-evaluation-of-vaginal-bleeding-in-pregnant-women