Jouppila P
J Clin Ultrasound. 1985 Feb;13(2):107-11. doi: 10.1002/jcu.1870130205.
Ultrasonic examination in 33 cases with threatened abortion at 8 to 17 weeks of pregnancy revealed an echo-free crescent area between the fetal membranes and uterine wall regarded as an intrauterine hematoma. A living fetus was simultaneously detected in all patients. The duration of uterine bleeding (mean 28.8 +/- 19.1 days) was significantly correlated (P less than 0.01) with the existence of the intrauterine blood collection followed serially by ultrasound. The pregnancy ended in spontaneous abortion in six (18.7%) and in premature delivery in three (9.4%) cases. The estimated volume of hematoma did not correlate with the outcome of pregnancy.