Background:In the mainland of China,the trial of labor after cesarean section is still a relatively new technique.In this study,we aimed to investigate the effects of labor onset,oxytocin use,and epidural anesthesia on matal and neonatal outcomes for vaginal birth after cesarean section (VBAC) in a tertiary hospital in China.Methods:This was a retrospective study carried out on 212 VBAC cases between January 2015 and June 2017 in Beijing Obstetrics and Gynecology Hospital,Capital Medical University.Relevant data were acquired on a form,including matemal age,gravidity and parity,body mass index before pregnancy,weight gain during pregnancy,type of labor onset,gestational age,the use of oxytocin and epidural anesthesia,birth mode,the duration of labor,and neonatal weight.The factors affecting matemal and neonatal outcomes for cases involving VBAC,especially with regards to postpartum hemorrhage (PPH) and fetal distress,were evaluated by univariate analysis and multivariable logistic regression.Results:Data showed that 36 women (17.0％) had postpartum hemorrhage (PPH) and 51 cases (24.1％) featured fetal distress.Normal delivery took place for 163 infants (76.9％) while 49 infants (23.1％) underwent operative vaginal deliveries with forceps.There were 178 cases (84.0％) of spontaneous labor and 34 cases (16.0％) required induction.Oxytocin was used in 54 cases (25.5％) to strengthen uterine contraction,and 65 cases (30.7％) received epidural anesthesia.The rate of normal delivery in cases involving PPH was significantly lower than those without PPH (61.1％ vs.80.1％;x2 =6.07,P =0.01).Multivariate logistic analysis showed that the intrapartum administration of oxytocin (odds ratio [OR] =2.47;95％ confidence interval [CI] =1.07-5.74;P =0.04) and birth mode (OR =0.40;95％ CI =0.18-0.87;P =0.02) was significantly associated with PPH in VBAC cases.Operative vaginal delivery occurred more frequently in the group with fetal distress than the group without (49.0％ vs.14.9％,x2 =25.36,P =0.00).Multivariate logistic analysis also revealed that the duration of total labor (OR =1.01;95％ CI =1.00-1.03;P =0.04) and the gestational week of delivery (OR =1.08;95％ CI=1.05-1.11;P =0.00)were significantly associated with fetal distress in VBAC.Conclusions:The administration ofoxytocin during labor and birth was identified as a protective factor for PPH in VBAC while birth mode was identified as a risk factor.Finally,the duration of total labor and the gestational week of delivery were identified as risk factors for fetal distress in cases of VBAC.This information might help obstetricians provide appropriate interventions during labor and birth for VBAC.