Thirteen studies (five RCTs, eight qualitative studies) were included in the review. The five RCTs had a total of 577 participants (range 52 to 195). Three trials had adequate randomisation but only one had adequate allocation concealment. None had blinding of outcome assessors. The proportion of participants not included in the analysis due to withdrawal or exclusion ranged from 8.3% to 34.6%.
In meta-analysis, which assessed 390 participants in the five trials, there was no difference between intervention and control in reducing gestational weight gain (SMD -0.28, 95% CI: -0.64 to 0.09). There was substantial statistical heterogeneity in this analysis (Ι²=67%, p=0.02). Subgroup and sensitivity analyses did not identify contextual elements that influenced the effectiveness of the intervention. Two trials with adequate sequence generation showed that the intervention group gained significantly less weight than the control group (-4.71kg, 95% CI: -8.11 to -1.91) with significant heterogeneity (Ι²=58%, p=0.007). More details of analyses were given in the report.
Results of the eight qualitative studies were also presented. A methodological and conceptual matrix was constructed to integrate the findings of the quantitative and qualitative syntheses. Potential implications of the views from the qualitative studies were presented alongside the findings of the interventions.