Ultrasound signs in threatened abortion and their prognostic significance.

During the first and early second trimesters of pregnancy in 244 consecutive patients with uterine bleeding, ultrasound studies were conducted to determine the cause of bleeding. In 165 of the patients the fetus was alive, and the outcome of pregnancy was successful in 143 (87%) despite the fact that ultrasound scanning revealed a total of 60 abnormalities. In the 22 patients whose pregnancy outcome was unfavorable, the number of abnormalities was significantly higher (P less than .05). The most common ultrasound abnormalities were placenta covering the internal os, fetal growth delay, multiple gestation, and intrauterine hematoma. At ultrasound examination, the presence of one or more abnormalities plus bleeding for three days or more significantly increased the risk to the pregnancy. When the duration of bleeding was less than three days and the ultrasound examination was normal, the risk to the pregnancy was lower (7%) than that of patients who had bled for three days or more and had at least one abnormality on ultrasound examination (24%) (P less than .05).