Ultrasonographic monitoring of the placenta in patients with bleeding during the first and second trimesters.

Thirteen patients with vaginal bleeding in the first and second trimester, in 730 pregnancies confirmed with live fetuses, were diagnosed as having subchorionic hematoma at the perivillous or periplacental region by a real-time B-mode scan device. In 9 of the 13 patients, the hematoma disappeared within 1 to 3 months after detection, while in 2 patients it increased in size. Seven of the 13 pregnancies progressed to full term (53.8%), 3 ended in premature deliveries (23.1%) and 3 in spontaneous abortions (23.1%). In 5 of the 13 patients, PROM occurred. Pathological examinations revealed 5 circumvallate (38.5%) and 2 circummarginate (15.4%) placentas. Since our clinical observation indicates that subchorionic hematoma and marginal separation of the placenta may be important causes of bleeding during pregnancy, monitoring of the placenta and fetus by ultrasound was used to obtain precise information in order to manage patients with bleeding. It might be speculated that extrachorial placenta results from subchorionic hematoma or its absorption.