EP19.16: Sonographic assessment of a Caesarean scar following vaginal birth after Caesarean section: a prospective trial

To sonographically asses Caesarean scar following vaginal birth after Caesarean section (VBAC) aiming to evaluate its potential utility in predicting the risk of scar rupture or dehiscence. A prospective cohort study was conducted of 55 women who fulfilled VBAC during 2022-2023 after 34 gestational weeks. Vaginal Sonographic evaluation of the Caesarean scar of the previous Caesarean section was performed twice during the hospital stay: immediately following delivery and within 48 hours postpartum. Caesarean scar morphology was assessed, including the depth and width of the scar, the residual and full thickness of the myometrium, and the presence of hematoma or bleeding in the scar. Clinical maternal outcomes and interventions and neonatal outcomes were collected. Informed consent was obtained before delivery. Out of 55 women, 25 were excluded partly due to unplanned repeat Caesarean section or loss of follow-up. The mean gestational age is 39.1 weeks. Most labour was begun spontaneously (63%), and there was no need for augmentation (60%). The mean neonatal birthweight is 3264g. In 10% of cases, intervention following delivery was required (manual uterine exploration and manual removal of placenta). No uterine rupture occurred. The mean hemoglobin level is 11.8g/dl. 47% required iron supplementation. The depth and width of LUS after delivery were larger than within 48 hours (15.5mm vs. 12.8mm p < 0.001; 16.2mm vs. 10.7mm p < 0.001, respectively). A positive correlation was found between hemoglobin decrease and the thickness of the full myometrium (p < 0.029). Sonography for Caesarean scar evaluation post-VBAC predicts maternal outcomes. No uterine rupture cases were found. A decrease in hemoglobin correlates with LUS. An ongoing LUS assessment investigation is needed for better VBAC delivery decisions.