Data-analysis
overweight
OBESE
Data were analysed by using Statistical Package for the Social Science (SPSS) version 27.0 (IBM, Armonk, New York) and Statistical Analysis System (SAS) version 9.4 (Cary, New York).Differences in mental health outcomes between the intervention and the control arm were investigated for all pre-pregnancy BMI groups together, as well as stratified by pre-pregnancy BMI class: normal pre-pregnancy weight (BMI 18.5–24.9 kg/mTo assess whether the evolution in mental health outcomes during the first year after childbirth differs between the intervention arm and the control arm, we applied mixed models. For each mental health outcome variable, we constructed a mixed model considering as explanatory variables: time since birth (in months), the randomization arm (intervention vs. control), the pre-pregnancy BMI class (normal, overweight or obese) and baseline characteristics that showed imbalance between the two randomization arms (mode of conception, the amount of excessive weight at the end of pregnancy (above the IOM cutoff for excessive GWG (in kg)), and QoL at W6 (Week 6)). We also considered a breakpoint at month 6 (in order to allow for a difference in the modeled evolution in the first 6 months after childbirth vs M6 until M12, and inter-action terms between time, randomization arm and pre-pregnancy BMI class. We started from the full model and applied backward variable selection by dropping one per one the term with the highest associated P-value. In case an interaction term showed statistical significance, the main effect terms were not dropped from the model. We used an unstructured covariance structure in order to take into account the dependency between subsequent measurements of the same mother.A p-value of < 0.05 was considered statistically significant. No adjustment for multiple testing was performed.