Résumé
OBJECTIVE: The purpose of this study was to determine which factors influence the likelihood of successful trial of labor, to evaluate the risks of VBAC and to evaluate the criteria of dystocia and the safety of VBAC. METHODS: This retrospective study was peformed based on 61 pregnant women who succeeded VBAC, 37 VBAC failure women, 100 nulliparas and 100 multiparas. RESULTS: In clinical characteristics, the parity, the number of previous cesarean section, gestational age, estimated fetal body weight by ultrasonography, and neonatal body weight had notable differences between the success and the failure group. In obstetric and historical factors, cervical effacement, dilation, and Bishop score at admission, spontaneous labor and method of induction of labor had differences. Among these factors, estimated fetal body weight by ultrasonography, cervical effacement and augmentation of labor using oxytocin were the most prognostic factors affecting the success of VBAC. In VBAC group, the duration of active-phase, second phase and total duration of labor were 313.5, 36.4 and 350.2 minutes, which were significantly shorter than nulliparas, but longer than multiparas. CONCLUSION: The trial of labor after cesarean section will decrease repeat operation, if it is performed under exact understanding of successful prognostic factors and the unique time length of labor. It will contribute to increase advantages for mother and economic benefits.