Statistical analysis
Statistical analysis was performed using Pearson’s chi-square test and Fisher’s exact test for categorical data and the Wilcoxon rank sum test for continuous data. Neonatal outcomes were analyzed using the generalized estimating equation method, considering twins and triplets born to the same mother. A multiple logistic regression analysis was performed to identify the independent risk factors for ESBL-E vaginal colonization. The adjustment factors were selected backward for variables with P -values of <0.05 in the univariate analysis, and a multivariate analysis was performed after confirmation that these adjustment factors had no collinearity in the covariate analysis. Statistical significance was set at P -values of <0.05. Statistical analysis was performed using SAS version 9.4 (SAS Institute, Cary, NC) and R version 4.0.4 (Vienna, Austria; http://www.R-project.org/).