Statistical analysis
macrosomia, weight gain, GDM
GDM, REGRESSION
The present study had a power of 95% to detect 40% increased risk in macrosomia outcome based on their mild GDM treatment status in the first of pregnancy, with a two-sided 5% significance level, and a sample size of 3,297 participants. Continuous variables were checked for normality using the Shapiro–Wilk test. Characteristics of participants were compared using the independent t-test or Pearson’s Chi-squared test for continuous and categorical data, and also Mann–Whitney U test for variables with skewed distribution. A modified Poisson regression for binary outcome data with a log link function and robust error variance was used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for the associations between mild GDM treatment status at the first trimester (treated mild GDM and non- treated mild GDM) and incidence of pregnancy outcomes; For comparison of first trimester treated mild GDM with those subgroup of first trimester non- treated mild GDM who developed GDM in the second trimester, adjusted risk ratios and 95% CI were reported. Adjusted variables were gestational ages at entrance and delivery, maternal BMI, gestational weight gain, method of GDM screening in the second trimester, and type of delivery. Treatment modality was also adjusted to compare those subgroups of GDM diagnosed in the second and first trimester of pregnancy treated mild GDM. Moreover, we adjust type of test in the model for comparing subgroup of first trimester non- treated mild GDM who developed GDM in the 2nd trimester with those first trimester treated mild GDM. Both unadjusted and adjusted models were fitted. In all analyses related to primary cesarean section outcomes, those with a previous history of cesarean section were excluded. Penalized maximum likelihood estimation was applied in the case of sparse data. Since the study was a cluster randomized trial, the cluster effect was considered in the analysis and the significance level of the test was set as 0.025 for considering subgroup analyses (