The effects of a lifestyle intervention (the HealthyMoms app) during pregnancy on infant body composition: Secondary outcome analysis from a randomized controlled trial

Summary Background Pregnancy has been identified as a window for childhood obesity prevention. Although lifestyle interventions in pregnancy can prevent excessive gestational weight gain (GWG), little is known whether such interventions also affect infant growth and body composition. Objectives To investigate (i) the effects of a 6‐month lifestyle intervention (the HealthyMoms app) on infant body composition 1–2 weeks postpartum, and (ii) whether a potential intervention effect on infant body composition is mediated through maternal GWG. Methods This is a secondary outcome analysis of the HealthyMoms randomized controlled trial. Air‐displacement plethysmography was used to measure body composition in 305 healthy full‐term infants. Results We observed no statistically significant effect on infant weight (β = −0.004, p = 0.94), length (β = −0.19, p = 0.46), body fat percentage (β = 0.17, p = 0.72), or any of the other body composition variables in the multiple regression models (all p ≥ 0.27). Moreover, we observed no mediation effect through GWG on infant body composition. Conclusions Our findings support that HealthyMoms may be implemented in healthcare to promote a healthy lifestyle in pregnant women without compromising offspring growth. Further research is required to elucidate whether lifestyle interventions in pregnancy also may result in beneficial effects on infant body composition and impact future obesity risk.