Dietary and lifestyle advice for pregnant women who are overweight or obese: the LIMIT randomized trial.

Overweight and obesity during pregnancy are common and are associated with an increased risk of adverse health outcomes for both the mother and the infant. However, robust evidence about the effect of antenatal dietary and lifestyle interventions on health outcomes is lacking. We conducted a multicenter, randomized trial, recruiting 2,212 women (from 3 public maternity hospitals across South Australia) with a singleton pregnancy between 10⁺⁰ and 20⁺⁰ weeks' gestation and a BMI ≥25. The women were randomized to lifestyle advice (n = 1,108) or standard care (n = 1,104). Women randomized to lifestyle advice participated in a comprehensive dietary and lifestyle intervention over the course of their pregnancy (delivered by research staff), while women randomized to standard care received pregnancy care according to local guidelines, which did not include such information. Provision of the lifestyle intervention was associated with a significant 18% relative risk reduction in the chance of infants being born with a birth weight above 4 kg. No other significant differences were identified in maternal pregnancy and birth outcomes between the two treatment groups. Observational studies highlight the association between a high infant birth weight and the subsequent risk of childhood and adulthood obesity. Antenatal interventions that are effective in reducing high infant birth weights therefore represent a significant strategy to tackle obesity from a population health perspective, while ongoing interrogation of the biospecimens and measurements, including ongoing childhood follow-up, will provide a unique opportunity to evaluate the mechanistic pathways of maternal-to-infant/childhood obesity.