[Clinical study on vaginal birth after cesarean].

OBJECTIVE: To investigate the incidence and pregnant outcome on vaginal birth after cesarean (VBAC).

METHODS: From January 2005 to December 2015, clinical data of 507 cases with VBAC in West China Second Hospital were studied retrospectively. There were 370 cases of VBAC from January 2013 to December 2015 as study group (VBAC group), in contrast, 740 cases of elective repeat cesarean section (ERCS group) and 740 primiparas of vaginal delivery without history of cesarean section as control groups, the pregnancy outcome were analyzed between the study group and control groups respectively.

RESULTS: (1) There were 76 547 total births from January 2005 to December 2015. Among these, 10 178 (13.296%, 10 178/76 547) patients had a single prior low transverse cesarean section, of which 4.981% (507/10 178) had VBAC. The incidence of VBAC was rising from 1.020%-3.704% during 2005-2012 to 6.028%-7.662% during 2013-2015. The rate of scared uterus during 2013-2015 was 18.269% (5 539/30 319), of which 9.26% (513/5 539) chose trial of labor after cesarean section (TOLAC). Successful VBAC occurred in 72.12% (370/513) of patients with TOLAC, and 27.88% (143/513) delivered by emergency cesarean. (2) The following parameters of the successful group and the unsuccessful VBAC group were compared, maternal age (29±4) versus (34±4) years, body mass index at prenatal visit (22.2±1.4) versus (22.6±1.4) kg/m(2), gestational age (38.7±0.9) versus (39.6±1.3) weeks, birth weight (3 326±317) versus (3 404±285) g, and the rate of induction of labor 0 (0/370) and 6.29% (9/143), there were significant differences (all P<0.01). There was no statistical difference between two group for lower uterine segment (P=0.947). (3) The duration of labor of VBAC group and 740 primiparas of vaginal delivery without history of cesarean section was compared, (10.3±1.8) versus (11.5±2.0) hours, there was significant difference (P<0.01). There were no statistical difference between two groups for the following parameters, including postpartum hemorrhage, hospitalization duration, the ratio of 5-minute Apgar score≥8, neonatal admission rate (all P>0.05). (4) The postpartum hemorrhage and hospitalization duration in VBAC group incidence were respectively (194±34) ml and (2.32±0.49) days, and the indexes of the ERCS group were respectively (419±57) ml and (4.14±0.78) days, there were significant differences (all P<0.01). There were no statistical difference between two groups for the ratio of 5-minute Apgar score≥8 and neonatal admission rate (all P>0.05).

CONCLUSIONS: The majority of patients choose ERCS rather than TOLAC. It's important to assess the indications and contraindications of patients for the successful VBAC, and to monitor maternal and fetal conditions during the delivery process. The premise of TOLAC is a comprehensive understanding of closely monitoring the progress of delivery. Compared with the ERCS, VBAC could reduce patients' postpartum hemorrhage and hospitalization duration, improve the outcomes of pregnancy, and the cesarean section rate could be reduced.