We identified 44 relevant randomised controlled trials (7278
women) evaluating three categories of interventions: diet, physical
activity, and a mixed approach. Overall, there was 1.42 kg reduction
(95% confidence interval 0.95 to 1.89 kg) in gestational weight gain with
any intervention compared with control. With all interventions combined,
there were no significant differences in birth weight (mean difference
−50 g, −100 to 0 g) and the incidence of large for gestational age (relative
risk 0.85, 0.66 to 1.09) or small for gestational age (1.00, 0.78 to 1.28)
babies between the groups, though by itself physical activity was
associated with reduced birth weight (mean difference −60 g, −120 to
−10 g). Interventions were associated with a reduced the risk of