Ultrasonic demonstration of myometrial contractions in intrauterine pregnancy

An incidental finding associated with ultrasound examination of early intrauterine pregnancy is transient thickening of a limited region of the myometrium, which we interpret as a localized contraction. Contractions were demonstrated in nearly all 881 patients examined and were shown to significantly change in configuration within a 30 min period. In all except one patient, the contractions were completely asymptomatic, and they seem to be of no discernible clinical significance.