Hyperglycaemia in utero is associated with increased insulin resistance and hyperglycaemia in offspring as described in animal studies [
12‐
14]. Some human studies suggest similar outcomes, a risk cited as an additional argument for diagnosing more gestational diabetes, since diagnosing and treating gestational diabetes may decrease obesity and diabetes in the long-term. Hillier et al. demonstrated that excess obesity in the offspring of women with gestational diabetes was ameliorated by therapy [
15]. However, maternal weight was not available to assess the role of maternal obesity. Previous studies have shown increased obesity in teenage offspring of women exposed to hyperglycaemia vs siblings of the same women who were not exposed to hyperglycaemia [
16], but other studies in Pima Indians showed that this impact on offspring weight was lost in older offspring aged 20–24 years [
17]. A prospective longitudinal study showed that the occurrence of gestational diabetes had no impact on obesity rates in 16-year-old offspring in the absence of maternal obesity [
18]. HAPO data for offspring at age 2 showed no relationship between offspring weight and maternal glycaemia level during pregnancy [
19]. Follow-up of children at 4–5 years old from the ACHOIS trial failed to show a difference in BMI
z scores between offspring of intervention and control gestational diabetes mothers, despite the former having a reduced macrosomic rate at birth [
20], although it may be too early to see any epigenetic effects. Most offspring of women with type 1 diabetes are exposed to much more severe hyperglycaemia in utero than offspring of women with gestational diabetes, yet the increased risk of glucose intolerance in the offspring of women with type 1 diabetes was half that of offspring whose mothers had treated gestational diabetes, with no associated difference in offspring BMI [
21]. Offspring of type 1 diabetic women were less overweight than those of mothers who had gestational diabetes [
22]. These studies indicate that hyperglycaemia in utero plays some role in adult offspring glucose tolerance and obesity, but that other factors are more important.