Maternal body size prior to pregnancy, gestational diabetes and weight gain: associations with insulin resistance in children at 9-10 years.

AIMS: To investigate whether maternal body size pre-pregnancy, gestational diabetes and weight gain are independently associated with subsequent insulin resistance in children; and to examine the potential mediating role of child's body size in any associations.
METHODS: At 9-10 years, 443 children took part in a follow-up of a prospective cohort. Of those, 163 children elected to provide a fasting blood sample and child insulin resistance was estimated by homeostasis model assessment. Generalized linear models with log link function and Gaussian family were used to assess associations with antenatal exposures. Potential confounders were considered as well as the role of the child's size.
RESULTS: Prior to pregnancy, 23% of mothers were overweight and another 17% obese. All women were screened for gestational diabetes, with 6% diagnosed. On average, women gained an estimated 14 kg during pregnancy. Gestational diabetes was positively associated with child insulin resistance. In addition, maternal pre-pregnancy body mass index (BMI) was associated with child insulin resistance in a non-linear manner: a positive, progressive association was observed until BMI of 30 kg/m² was reached, but not thereafter. Estimated gestational weight gain was not associated with child insulin resistance. These findings were not accounted for by size of the child at birth or at 9-10 years.
CONCLUSIONS: Maternal body size prior to pregnancy is positively associated with increases in child insulin resistance, at least until the 'obese' category is reached. This is independent of gestational diabetes and not mediated by body size of the child, suggesting genetic and/or developmental programming origins.