Objective: To explore the risk factors and pregnancy outcomes in women with a history of cesarean section complicated by placenta accreta.Methods: This retrospective study included clinical data from singleton mothers with a history of cesarean section in 11 public tertiary hospitals in 7 provinces of China between January 2017 and December 2017. According to the intraoperative findings or the pathologic diagnosis after delivery, the study population was divided into placenta accreta (PA) and non-PA groups. We compared the pregnancy outcomes between the 2 groups, used multivariate logistic regression to analyze the risk factors for placental accreta, and used receiver operating characteristic curves to evaluate the value of the risk factors.Results: For this study we included 11,074 pregnant women with a history of cesarean section; and of these, 869 cases were in the PA group and 10,205 cases were in the non-PA group. Compared with the non-PA group, the probability of postpartum hemorrhage, severe postpartum hemorrhage, diffuse intravascular coagulation, puerperal infection, intraoperative bladder injury, hysterectomy, and blood transfusion was significantly increased in the placenta accreta group (P<0.05)). At the same time, the rate of neonatal low-birth weight, the probability of neonatal comorbidities, and the rate of neonatal intensive care unit admission also increased significantly (P<0.05). Weight, parity, number of miscarriages, number of previous cesarean sections, history of premature rupture of membrane, previous cesarean-section transverse incisions, history of placenta previa, and the combination of prenatal hemorrhage and placenta previa were all independent risk factors for placenta accreta; while non-Han ethnicity was an independent protective factor for placenta accreta (P<0.05). The area under the ROC curve (AUC) was 0.93 (95% CI=0.92-0.94); and the specificity, sensitivity, and accuracy rate were 0.87, 0.93, and 0.93, respectively.Conclusions: There was an increased risk of adverse outcomes in pregnancies complicated by placenta accreta in women with a history of cesarean section, and this required close clinical attention. Weight before pregnancy, parity, number of miscarriages, number of previous cesarean sections, Han ethnicity, history of premature rupture of membranes, past transverse incisions in cesarean sections, a history of placenta previa, prenatal hemorrhage, and placenta previa were independent risk factors for pregnancies complicated with placenta accreta in women with a history of cesarean section. These independent risk factors showed a high value in predicting the risk for placental accreta in pregnancies of women with a history of cesarean section.

Background The cesarean delivery (CD) rate has been increasing globally. Trial of labor after cesarean delivery (TOLAC) has been used as a key method for the reduction of the CD rate. Little is known, however, about the association between the second-stage duration of TOLAC and adverse maternal and neonatal outcomes. This study evaluated the association between perinatal outcomes and the duration of second-stage labor in women undergoing TOLAC. Methods A 10-year retrospective cohort study was performed at the Department of Obstetrics and Gynecology, Third Affiliated Hospital of Guangzhou Medical University, between January 2010 and January 2020. Women undergoing TOLAC who reached the second stage of labor were included in this study. Duration of the second stage of labor was examined as a categorical variable (group I: <0.5 h, group II: 0.5–2 h and group III: ≥2 h) and as a continuous variable to evaluate the association with adverse perinatal outcomes by using multivariable regression models and a Cox proportional hazards regression model adjusting for potential confounders. Results Of the 1,174 women who met the inclusion criteria, the median (interquartile range) length of the second stage was 0.5 h (0.3–0.9 h). Among them, 1,143 (97.4%) delivered vaginally and 31 underwent an unplanned CD. As the second-stage duration increased, operative vaginal delivery (OVD), CD, and postpartum hemorrhage (PPH) rates increased. Women in group III had higher risks of OVD (aOR = 11.34; 95% CI [5.06–25.41]), CD (aOR = 4.22; 95% CI [1.32–13.43]), and PPH (aOR = 2.43; 95% CI [1.31–4.50]) compared with group I. Correspondingly, blood loss and the oxytocin used to treat PPH increased significantly, while the postpartum hemoglobin reduced significantly in group III compared with group I. The incidence of uterine rupture, uterine atony, cervical laceration, red blood cell transfusion, and intensive care unit admission were similar in all three groups. Neonatal outcomes were not affected by the second-stage duration. Conclusions Women undergoing TOLAC with second-stage duration of ≥2 h have higher odds of OVD, unplanned intrapartum CD, and PPH.