The effect of prenatal lifestyle intervention on weight retention 12 months postpartum: results of the Norwegian Fit for Delivery randomised controlled trial.

<bold>Objective: </bold>To examine the effect of a prenatal lifestyle intervention on postpartum weight retention (PPWR).<bold>Design: </bold>Randomised controlled trial.<bold>Setting: </bold>Healthcare clinics in southern Norway.<bold>Population: </bold>Healthy, nulliparous women with body mass index ≥19 kg/m2 , age ≥18 years, and singleton pregnancy of ≤20 gestational weeks.<bold>Methods: </bold>Women were randomised to intervention (dietary counselling twice by phone and access to twice-weekly exercise groups during pregnancy) or control group (standard prenatal care). Intervention compliance was defined post-factum as attending dietary counselling and ≥14 exercise classes.<bold>Main Outcome Measures: </bold>PPWR (weight measured postpartum minus self-reported pre-pregnancy weight) and the proportion of women returning to pre-pregnancy weight.<bold>Results: </bold>Of 606 women randomised, 591 were included in an intention-to-treat analysis of pregnancy outcomes and 391 (64.5%) were analysed 12 months postpartum. Mean PPWR was not significantly different between groups (0.66 kg for intervention versus 1.42 kg for control group, mean difference -0.77 kg, 95% CI -1.81, 0.28; P = 0.149). An increased proportion of intervention participants achieved pre-pregnancy weight (53% versus 43%, OR 1.50, 95% CI 1.003, 1.471; P = 0.045). However, the difference was not statistically significant when we adjusted for missing data (adjusted odds ratio (OR) 2.23, P = 0.067) using logistic mixed-effects models analysis. Women compliant with intervention had significantly lower PPWR than control participants, also after adjusting for potential confounders (adjusted mean diff -1.54 kg, 95% CI -3.02, -0.05; P = 0.039).<bold>Conclusions: </bold>The Norwegian Fit for Delivery intervention had little effect on PPWR, although women who were compliant with the intervention demonstrated significantly lower PPWR at 12 months.<bold>Tweetable Abstract: </bold>Norwegian Fit for Delivery RCT: little effect of lifestyle intervention on weight retention 1 year postpartum. [ABSTRACT FROM AUTHOR]