Clinical value of ultrasonic indicators in predicting the outcome of caesarean scar pregnancy after pregnancy termination

Background To investigate the predictive value of ultrasound indicators in early pregnancy for the outcome of caesarean scar pregnancy (CSP) after pregnancy termination.Methods This study retrospectively analysed the ultrasound images of 98 CSP patients who underwent transabdominal ultrasound-guided hysteroscopic curettage during early pregnancy at Changsha Hospital for Maternal and Child Health Care between January 2017 and October 2021. Patients were equally divided into a case group and a control group. The case group included 49 CSP patients with postoperative complications, such as intraoperative blood loss >= 200 ml or retained products of conception (RPOC). The remaining 49 CSP patients, with similar age and gestational age and with good postoperative outcomes, such as intraoperative blood loss <= 50 ml and no RPOC, were included in the control group. CSP was classified into three types according to the location of the gestational sac (GS) relative to the uterine cavity line (UCL) and serosal contour. Differences in ultrasound indicators between the case and control group were compared.Results There were significant differences between the case and control groups in the mean gestational sac diameter (MGSD), residual myometrium thickness (RMT) between the GS and the bladder, blood flow around the GS at the site of the previous caesarean incision, and types of CSP (P < 0.05). The rs of each ultrasound indicator were as follows: 0.258, -0.485, 0.369, 0.350. The optimal threshold for predicting good postoperative outcomes, such as intraoperative blood loss <= 50 ml and no RPOC, by receiver operating characteristic (ROC) curve analysis of the RMT was 2.3 mm.Conclusion Our findings show that the RMT, blood flow around the GS at the site of the previous caesarean incision, and types of CSP have a low correlation with postoperative complications, such as intraoperative blood loss >= 200 ml or RPOC, of early pregnancy termination in patients with CSP. To some extent, this study may be helpful for clinical prognostic prediction of patients with CSP and formulation of treatment strategies. Given the low correlation between these three indicators and postoperative complications, further studies are needed to identify indicators that can better reflect the postoperative outcomes of CSP patients.