[Involution of the uterus following vaginal or abdominal delivery]

Involution of the uterus was observed in 77 puerperae by B-scan ultrasonography. In most cases the examinations were carried out several times on different days. Of all uterine dimensions (extension, circumferences, areal dimensions, volume index) the length proved particularly suitable for evaluating the involution. The other parameters offered no advantages. The findings covered 60 examinations following spontaneous labor and 137 following cesarean section. In both groups involution was completed by the 6th to 7th week after parturition. On the basis of mean values the course of involution was identical in the two groups, although there was considerable individual scatter. These findings, which do not correlate to the usual palpation findings in daily fundus checks on puerperae, may be explained by the different position of the uterus. Following spontaneous labor there is pronounced anteversion of the uterus and it is located lower. Following cesarean section it adopts a more extended position causing the fundus to be higher on palpation. It was also found that daily intramuscular injection of Syntocinon following cesarean sections has no measurable influence on the rate of involution.