EP16.48: Assessing the correctness of preoperative diagnosis in vasa previa

Vasa previa requires accurate diagnosis and often leads to Caesarean section. In Type 1 vasa previa, where the umbilical cord is velamentously inserted, there may not be a single vessel running on the fetal membranes, necessitating caution during Caesarean section. Therefore, we assessed the preoperative diagnostic accuracy of three cases experienced at our hospital. Preoperative evaluation utilised a combination of transvaginal and transabdominal ultrasound with colour Doppler to confirm vascular flow. Case 1: A 34-year-old primipara, conceived via IVF, underwent Caesarean section at 35 weeks and 1 day. Preoperatively, the placenta was attached to the posterior wall, with the vasa previa running almost directly over the internal cervical os, and umbilical cord attachment on the anterior uterine wall. Postoperative evaluation revealed two vessels running from the uterine fundus to the anterior and lateral walls, necessitating careful manoeuvring to avoid them during the Caesarean section. Case 2: A 34-year-old primipara, conceived via ICSI, underwent Caesarean section at 37 weeks and 5 days. Preoperatively, the placenta was attached to the right side of the posterior wall, and vessels running on the fetal membranes were observed crossing near the internal cervical os. Postoperative evaluation revealed additional vessels on both sides of the internal cervical os, requiring careful incision to avoid interference during the Caesarean section. Case 3: A 40-year-old primipara, with a spontaneous pregnancy, underwent Caesarean section at 37 weeks and 2 days. Preoperative evaluation showed two vessels running near the internal cervical os. Postoperative evaluation was consistent with preoperative findings. In two cases, vessels running on the fetal membranes were missed preoperatively. We believe that assessing postoperative vascular flow and providing feedback can improve the accuracy of preoperative evaluation.