Randomised controlled trials (RCTs) that evaluated antenatal dietary or lifestyle antenatal interventions in pregnant women defined as overweight (body mass index (BMI) ≥25kg/m2) or obese (BMI ≥30 kg/m2) were eligible for inclusion in the review. The primary outcome of the review was large for gestational age infants (birthweight of greater than the 90th centile for gestation and infant sex or birthweight >4,000g defined by the trial authors). Secondary outcomes of interest were mean gestational weight gain, hypertension, pre-eclampsia or eclampsia, gestational diabetes, preterm birth before 37 weeks of gestation, infection, need for induced labour, caesarean section, postpartum haemorrhage that required blood transfusion, perinatal death, congenital abnormalities, infant birthweight more than 4,500g or less than 2,500g, Apgar score of less than 7 at five minutes of age, hypoglycaemia that required intravenous treatment, hyperbilirubinaemia that required treatment, admission to neonatal intensive care and birth trauma. Relevant childhood outcomes were body size (height, weight and BMI) and body composition.
Most trials evaluated a dietary intervention compared with standard care (no intervention). Others focused on aerobic and/or resistance exercise. Interventions were varied in terms of frequency, intensity and duration. Trials largely included women in all BMI categories; there was variable reporting of outcomes in those considered to be overweight and obese. Studies were conducted in USA, Canada, Europe, Australia and Brazil. There were no UK studies.
Two independent reviewers selected the studies.