To analyze clinical characteristics and high risk factors of scarred uterus with uterine rupture during pregnancy.

From January 2016 to December 2019, a total of 106 scarred uterine pregnant women with uterine rupture during pregnancy in Chengdu Women′s and Children′s Central Hospital were selected as research subjects. There were 95 cases (89.6%) uterine rupture during re-pregnancy in scarred uterine pregnant women after cesarean section, and 11 cases (10.4%) patients with uterine rupture during pregnancy in scarred uterine pregnant women after non-cesarean section, such as uterine perforation, uterine horn wedge resection, and uterine myomectomy usually. According to types of uterine rupture after cesarean section during re-pregnancy, 95 cases scarred uterine pregnant women with uterine rupture after cesarean section during re-pregnancy were divided into complete uterine rupture (CRU) group (n=27) and incomplete uterine rupture (ICRU) group (n=79). Clinical data of CRU group and ICRU group were compared by Mann-Whitney U test, chi-square test or continuous correction chi-square test. The procedures followed in this study were in line with the requirements of World Medical Association Declaration of Helsinki revised in 2013.

①The rate of uterine rupture in scarred uterine pregnant women during pregnancy was 0.129% (106/82 157) from January 2016 to December 2019 in our hospital. There were statistically different in rates of uterine rupture among these four years by overall comparison (χ²=26.490, P<0.001). ②The average age of 106 patients was 32 years old (19-40 years), and 104 cases (98.1%) pregnant women whose uterine ruptures happened in third trimester (≥28 gestational weeks) and 2 cases (1.9%) in second trimester (20-27^{+ 6} gestational weeks). Uterine ruptures among these 106 pregnant women, 74 cases (69.8%) had no any typical clinical manifestations, and the other 32 cases (30.2%) had typical clinical manifestation. Among 11 patients with scarred uterine after non-cesarean section, 8 cases had serious adverse pregnancy outcomes, including stillbirth, neonatal asphyxia, hemorrhagic shock and hysterectomy in 3, 5, 3 and 2 cases, respectively. ③There were no statistical differences among gravidity, parity, and times of previous cesarean delivery between CUR group and ICUR group (P>0.05). The age of pregnant women in CUR group was significantly older than that of ICUR group (Z=14.323, P<0.001). The gestational age in CUR group was significantly smaller than that of ICUR group (Z=-32.578, P<0.001). The pregnancy interval in CUR group was significantly shorter than that of ICUR group (Z=-7.268, P<0.001). The parturient attack rate in CUR group was significantly higher than that of ICUR group (χ²=4.720, P=0.030). ④The treatment methods of 106 pregnant women included hysterectomy in 3 cases, bilateral tubal ligation and hysterorrhaphy during cesarean section in 18 cases, and just hysterorrhaphy during cesarean section in 85 cases. And 85 patients with retained fertility were followed up for 5 to 52 months, and none of them got pregnant again.

Scarred uterus in pregnant women is a primary risk factor for uterine rupture during pregnancy. The main cause of scarred uterus is cesarean section. CUR is closely related to pregnancy interval in re-pregnant women with scarred uterine after cesarean section. Uterine rupture of scarred uterus caused by non-cesarean section leads to more serious clinical complications.