P25.01: Sonographic evaluation of uterine scar 4 and 12 weeks after Caesarean section

Abstract

The aim of the study was to evaluate uterine scar 4 and 12 weeks after delivery using transvaginal ultrasound. The study group consisted of 108 women who underwent Caesarean section (CS) from September 2011 until September 2012 and reported for the transvaginal ultrasound examination. There were 108 women evaluated 4 weeks and 58 of them 12 weeks after delivery. The lower uterine segment was assessed and the presence of the Caesarean scar, scar defect and defect's dimensions were noted and analyzed. The scar defect was defined as hypoechoic area within the myometrium at the site of CS. 12 weeks after CS there was also external defect evaluated. External defect was defined as the loss of myometrium in the anterior wall under the bladder. Defect was measured in three dimensions: width and depth (sagital plane), and length (transverse plane). The external defect and residual myometrial thickness (RMT) were measured on sagital plane. The uterine scar was visible in all patients. The uterine scar defect was found in 58(49%) and 15(26%) of women 4 and 12 weeks after delivery respectively. External defect was found in 6(10%) cases. The mean width of the defect 4 weeks after CS was 8,7±3,7 mm; depth 7,6±4,1 mm; length 11,9±5,2 mm. The same measurements 12 weeks after CS were: 4,6±2,3 mm; 4,0±1,9 mm; 5,8±2,3 mm. The external defect width was 3,9±11,3 mm and depth 4,7±1,5 mm. RMT 4 weeks after Caesarean section was 8,1±4,4 mm in the defect group versus 13,1±3,8 mm in non-defect group. 12 weeks after Caesarean section the same values were: 5,3±3,0 mm and 8,1±2,7 mm respectively. The ultrasound's sign of successful recovery of the uterus defined as non-defect visualisation can be observed as early as 4 weeks after CS in half of women. As the postpartum evolution of uterus is ending the prevalence of uterine scar defect decreases 12 weeks after CS. There is significant difference in RMT between women with and without uterine scar defect. In women with uterine scar defect myometrium at the site of Caesarean scar is 35-37% thinner compared to those without defect.