2.9. Statistical Analysis
REGRESSION, IOL
We expressed continuous variables as mean with standard deviation or median with interquartile range and summarized categorical data as frequency, percentage, or proportion. The primary outcome variable (mode of delivery) was expressed as the proportion with a 95% confidence interval and was analyzed using the chi-square test as the statistical test. We compared the baseline characteristics using the chi-square test or Fischer's exact test if expressed in proportions and the unpaired student test or Mann–Whitney test. Subgroup analysis was attempted for factors associated with successful VBAC after IOL by univariate and logistic regression analyses.