Background: Emergency cervical cerclage (ECC) is of potential value in twin pregnancy, when the cervix is dilated to >1cm. McDonald and Shirodkar were two main techniques of transvaginal cerclage at present. As ECC at extremely high risk of spontaneous preterm birth (sPTB) especially for twins with cervical dilated ≥ 3cm and prolapsed membranes, so which technique has more advantages is still uncertain. Objectives: The aim of our study was to evaluate the effectiveness of ECC performed with combined McDonald-Shirodkar technique in twin pregnancies between 18–26 weeks with painless cervical dilation 1-6cm. Methods: A retrospective, cohort study matched with the degree of cervical dilation was conducted. The study group (case group) included twin pregnancies who underwent combined McDonald-Shirodkar approach with cervical dilation ≥1 cm between 18–26 weeks of gestation at four institutions, from December 2015 to December 2022. To minimize confounding factors, we elucidated the causality structure using a DAG (Figure 1) and performed 1:1 case-control Matching. A control group performed McDonald approach. The primary outcome was gestational age (GA) at delivery. The secondary outcomes were pregnancy latency, the rates of sPTB at <28, <30, <32, <34 weeks, and neonatal outcomes. Additional sub-analysis was performed by dividing the patients into two subgroups of cervical dilation ≥ 3cm and < 3cm. Results: 84 twin pregnancies were managed with either combined McDonald-Shirodkar approach (case group: n=42) or McDonald approach (control group: n=42). Demographic characteristics were not significantly different in two groups(p>0.05). After adjusting for confounders which were represented by a directed acyclic graph (DAG, Figure 1), median GA at delivery was significantly higher (30.5 vs 27 weeks, Bate: 3.40, 95% confidence interval (CI): 2.13-4.67, p<0.001) and median pregnancy latency was significantly longer (56 vs 28 days, Bate: 24.04, 95% CI: 13.31-34.78, p<0.001) in the case group compared with the control group. Rates of sPTB at <28, <30, <32, and <34 weeks were significantly lower in the case group than in the control group. For neonatal outcomes, there were higher birth weight (BW) (1543.75 vs 980g, Bate: 420.08, 95%CI: 192.18-647.98, p<0.001) and significantly lower overall perinatal mortality (7.1% vs 31%, aOR: 0.16, 95% CI: 0.04-0.70, p=0.014) in the case group compared with the control group. And when cervical dilation ≥ 3cm, combined McDonald-Shirodkar procedure can significantly reduce perinatal mortality (8.3% vs 46.7%, aOR:0.09, 95%CI: 0.01-0.77, p=0.028), significantly decrease the risk of delivery at <28, <30weeks, prolong GA at delivery and pregnancy latency compared with McDonald procedure. Conclusions: ECC performed with the combined McDonald-Shirodkar procedure in twin pregnancies with cervical dilation 1-6 cm in mid-trimester pregnancy may reduce the rate of sPTB and improve perinatal and neonatal outcomes compared with McDonald procedure, especially for twins with cervical dilation of 3-6 cm and prolapsed membranes.

Objective: To develop and validate a predictive model assessing the risk of cesarean delivery in primiparous women based on the findings of magnetic resonance imaging (MRI) studies. Design: Observational study Setting: University teaching hospital. Population: 168 primiparous women with clinical findings suggestive of cephalopelvic disproportion. Methods: All women underwent MRI measurements prior to the onset of labor. A nomogram model to predict the risk of cesarean delivery was proposed based on the MRI data. The discrimination of the model was calculated by the area under the receiver operating characteristic curve (AUC) and calibration was assessed by calibration plots. The decision curve analysis was applied to evaluate the net clinical benefit. Main Outcome Measures: Cesarean delivery. Results: A total of 88 (58.7%) women achieved vaginal delivery, and 62 (41.3%) required cesarean section caused by obstructed labor. In multivariable modeling, the maternal body mass index before delivery, induction of labor, bilateral femoral head distance, obstetric conjugate, fetal head circumference and fetal abdominal circumference were significantly associated with the likelihood of cesarean delivery. The discrimination calculated as the AUC was 0.845 (95% CI: 0.783-0.908; P < 0.001). The sensitivity and specificity of the nomogram model were 0.918 and 0.629, respectively. The model demonstrated satisfactory calibration. Moreover, the decision curve analysis proved the superior net benefit of the model compared with each factor included. Conclusion: Our study provides a nomogram model that can accurately identify primiparous women at risk of cesarean delivery caused by cephalopelvic disproportion based on the MRI measurements.