Statistical analyses
Participant characteristics were summarized according to the maternal sleeping status. All variables were found to follow a normal distribution based on the Shapiro-Wilk test. One-way analysis of variance was used to compare continuous variables among different MSD groups, and the chi-square test was used to compare categorical variables.
Initially, adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for LBW <2,500 g, LBW <1,500 g, SGA, and macrosomia were calculated using a multiple logistic regression model, with women in G2 as the reference. In Model 1, aOR for LBW was adjusted for maternal age, BMI before pregnancy, parity, maternal smoking status, maternal alcohol consumption status, maternal educational status, annual household income, and PTB before 37 weeks. aOR for SGA was adjusted for maternal age, BMI before pregnancy, maternal smoking status, maternal alcohol consumption status, maternal educational status, and annual household income. aOR for macrosomia was adjusted for maternal age, BMI before pregnancy, parity, maternal smoking status, maternal alcohol consumption status, maternal educational status, and annual household income. In Model 2, excessive gestational BWG was added as a confounding factor (in addition to those of Model 1) to calculate aORs for these outcomes.
Further, we stratified the participants on the basis of gestational BWG, and aORs for LBW <2,500 g and SGA were calculated using a multiple logistic regression model, with women in G2 as the reference, using the comparable confounding factors in Model 1.
SPSS version 26 (IBM Corp., Armonk, NY, USA) was used for statistical analyses. Differences with p-values <0.05 were considered statistically significant.