2.5. Data Analyses
USA).The, depression, weight retention, anxiety
REGRESSION
Statistical analyses were performed by using Statistical Package for the Social Science (SPSS) version 27.0 (IBM, Armonk, New York, NY, USA) and Statistical Analysis System (SAS) version 9.4 (Cary, New York, NY, USA).The Kolmogorov–Smirnov test in addition to plots and histograms was used to assess the normality of distribution of continuous variables. All mental health variables showed a skewed distribution and were therefore analyzed by using non-parametric tests.Descriptive characteristics were presented as mean and standard deviation or median and interquartile range for continuous variables and frequencies and percentages for categorical variables. To assess differences in participant characteristics between two groups, the unpaired To assess the difference in mental health at 2 different time points in the same patients, the Mc-Nemar test was used for categorical variables and the Wilcoxon signed ranked test for continuous variables.Participants were divided into low/high according to the pre-defined cut-off (We performed regression analyses to assess whether mental health at the start and end of the interpregnancy interval were independent factors associated with BMI and body composition at the start of the next pregnancy. The outcome variables were postpartum weight retention, change in BMI at the start of each pregnancy and body composition at the start of the second pregnancy (BMI, fat percentage, waist circumference and visceral fat). We considered the mental health variables as categorical variables: high/low at the start, high/low at the end and the four possible combinations (high at start and end, high at start but low at end, etc.). We took into account as explanatory variables the following: pre-pregnancy BMI at the start of the previous pregnancy (continuous variable), level of education, exclusive breastfeeding at 6 months, interpregnancy interval (short (≤18 months) vs. normal (18–59 months)), sleep, history of depression, history of anxiety and mental health variables). Stepwise variable selection was performed to assess whether the mental health variables showed independent statistical significance to the outcome variables (BMI and body composition at the start of the next pregnancy).