Data processing and analysis
All collected data were rechecked for completeness and coded. Then the
data were entered and cleaned using Epidata 3.1 software. Data are
expressed as mean ± standard deviation, or median (25th-75th
percentile). The normality of variables was assessed. Differences
between two groups were compared with the Student’s t-test and the
Mann–Whitney U test for continuous variables: mean and median,
respectively, and with the χ2 test or Fisher’s exact test for
categorical variables. We used the Spearman coefficient to assess the
correlation between UR rate and VBAC rate. Multiple logistic regression
analysis was performed to examine the influence of the symptoms as
variables on UR. Odds ratios (OR) and Mean differences (MD) are
presented with 95% confidence intervals (CI) Statistical analyses were
performed using SPSS software, version 22.0 (SPSS Inc., Chicago, IL,
USA). A p value of less than 0.05 was considered statistically
significant.