Measurement of the uterus and gestation sac by ultrasound in early normal and abnormal pregnancy.

Uterine volumes measured by two different ultrasonic methods, and gestation sac volumes in early normal pregnancy are reported. The results obtained for uterine volume measurements are compared. Methods using measurements obtained from only a longitudinal scan were simpler but slightly less accurate. Uterine volumes were also calculated in a series of patients with pregnancy complicated by threatened abortion. The accuracy of the prediction of the outcome of the pregnancy, based solely on uterine volume was 71 percent. Uterine volume measurement is most useful in identifying cases of missed abortion where the period of gestation is known.