The associations between maternal BMI and gestational weight gain and health outcomes in offspring at age 1 and 7 years

In secondary analyses of a randomised controlled trial of exercise during pregnancy, we examined associations between mid-pregnancy maternal body mass index (BMI) and excessive gestational weight gain (GWG) with offspring health. Follow-up data were available on 57 mother-child pairs at 1-year and 52 pairs at 7-year follow-ups. Clinical assessments included body composition and fasting blood tests. At age 1 year, increased maternal BMI in mid-gestation was associated with greater weight standard deviation scores (SDS) in the offspring (p = 0.035), with no observed associations for excessive GWG. At age 7 years, greater maternal BMI was associated with increased weight SDS (p < 0.001), BMI SDS (p = 0.005), and total body fat percentage (p = 0.037) in their children. Irrespective of maternal BMI, children born to mothers with excessive GWG had greater abdominal adiposity (p = 0.043) and less favourable lipid profile (lower HDL-C and higher triglycerides). At 7 years, maternal BMI and excessive GWG had compounded adverse associations with offspring adiposity. Compared to offspring of mothers with overweight/obesity plus excessive GWG, children of normal-weight mothers with adequate and excessive GWG were 0.97 and 0.64 SDS lighter (p = 0.002 and p = 0.014, respectively), and 0.98 and 0.63 SDS leaner (p = 0.001 and p = 0.014, respectively). Both greater maternal BMI in mid-pregnancy and excessive GWG were independently associated with increased adiposity in offspring at 7 years.