Effect of gestational diabetes on fetal growth rate and later overweight in the offspring.

ABSTRACT

CONTEXT Children of women with gestational diabetes (GDM) are often born with a higher birthweight and have an increased risk of overweight during childhood. High fetal growth rate is also associated with being overweight in childhood. OBJECTIVE: To examine excessive fetal growth rate as a mediator between GDM and overweight in the offspring. METHODS: This was a longitudinal cohort study, using routinely collected data on children born 2008-2014 in Aarhus, Denmark. Fetal biometrics were extracted from the patient records at Aarhus University Hospital and childhood weight from the health records at Aarhus Municipality Healthcare Service. We calculated growth trajectories for fetuses affected by GDM and for unaffected fetuses using cubic mixed model regression. We extracted individual fetal growth rate and estimated the contributing effect of fetal growth rate on the risk of being overweight in the 5-9 year-old offspring. RESULTS: We included 6794 mother-child pairs, 295 with GDM. Fetal growth was higher in women with GDM from week 25, and the offspring had an increased risk of being overweight (OR 2.02 (95%CI 1.44 - 2.84)). When adjusting for fetal growth rate in week 28 the effect attenuated by 15%, and to 1.10 (95%CI 0.76 - 1.60) when further adjusting for pre-pregnancy BMI. CONCLUSION: Pregnancies affected by GDM had higher fetal growth rate and the offspring had a higher risk of being overweight at 5-9 years. Fetal growth rate in early third trimester was a mediator of up to 15% of this association, but pre-pregnancy BMI contributed strongly as well.