[Prediction and analysis of adverse pregnancy outcomes in pregnant women with cesarean scar diverticulum].

Objective: To investigate the pregnancy outcomes of pregnant women with cesarean scar diverticulum (CSD) and to find the relevant factors that predict the occurrence of adverse pregnancy outcomes. Methods: From January 2015 to March 2019, 501 singleton pregnant women with a history of cesarean section who underwent regular prenatal examination in early pregnancy and eventually delivered in Peking University First Hospital were prospectively collected. According to the presence or absence of CSD in the first trimester of pregnancy, the pregnant women were divided into the CSD group (n=127, 25.3%) and the non-CSD group (n=374, 74.7%). According to the mode of delivery and the classification of the lower uterine segment seen during cesarean section, the CSD group was further divided into the non-rupture group (including spontaneous delivery and lower uterine segment grade Ⅰ;n=108, 85.0%) and rupture group (including lower uterine segment grade Ⅱ-Ⅳ;n=19, 15.0%). The general clinical data, pregnancy outcomes, diverticulum-related indexes [including length, width, depth (D), average diameter, volume, and residual myometrial thickness (RMT)] were compared. The predictive values of D/adjacent myometrial thickness≥50%, RMT≤2.2 mm and D/RMT>1.3 for uterine rupture in CSD pregnant women were verified. Results: (1) Comparison between CSD group and non-CSD group: the lower uterine segment thickness in the third trimester of pregnancy in the CSD group was lower than that in the non-CSD group [(1.2±0.5) vs (1.4±0.6) mm, respectively], and the incidence of uterine rupture was higher than that in the non-CSD group [15.0% (19/127) vs 8.0% (30/374), respectively], and the differences were statistically significant (both P<0.05). There were no significant differences in other clinical data and pregnancy outcomes between the two groups (all P>0.05). (2) Comparison of rupture group and non-rupture group: the lower uterine segment thickness in the third trimester of pregnancy in rupture group [(0.6±0.5) mm] was lower than that in non-rupture group [(1.2±0.6) mm], and the difference was statistically significant (t=3.486, P=0.001). There were no significant differences in diverticulum-related indexes between the two groups (all P>0.05). (3) Relationship between high risk predictors of uterine rupture and actual uterine rupture: the sensitivity of D/adjacent muscle thickness ≥50%, RMT≤2.2 mm and D/RMT>1.3 in predicting the high risk of uterine rupture were 94.7%, 57.9% and 73.6%, the specificity were 12.0%, 40.7% and 24.1%, the positive predictive value were 15.9%, 14.7%, 14.6%, and the negative predictive value were 92.8%, 84.6%, 83.9%, respectively. Conclusions: The risk of uterine rupture in pregnant women with CSD is higher than that in those without CSD. There is no significant correlation between CSD related indexes and uterine rupture in the first trimester. Monitoring the lower uterine segment thickness in the third trimester might be helpful to predict the occurrence of adverse pregnancy outcomes.