Glucose tolerance of offspring of mother with gestational diabetes mellitus in a low-risk population

Abstract

Aims: To describe the prevalence of impaired glucose tolerance and obesity in offspring of mothers whose pregnancies were complicated by gestational diabetes mellitus (GDM) in a low-risk population and to investigate the effect on these outcomes of minimal intervention compared with tight control for management of GDM.

Methods: Eighty-nine children (mean age 9.1 years, 93% Caucasian) were recruited through a follow-up study of women previously involved in a randomized controlled trial of minimal intervention (control group) vs. tight glycaemic control (treatment group) for GDM. Fasting blood glucose (FBG) and 2-h glucose tolerance tests (2hGTT) were performed on offspring and body mass index (BMI) calculated. Glucose tolerance and BMI of treatment groups were compared using non-inferiority tests (non-inferiority margin -15%).

Results: Of those offspring, 6.9% (5/72) had abnormal glucose metabolism [four children had impaired glucose tolerance (IGT) and one had Type 2 diabetes mellitus (DM) (all Caucasian)]. Of the four children with IGT, three were male, three had normal BMI, and three had a family history of Type 2 diabetes. Of the 71 offspring who underwent 2hGTT, 25/25 (100%) of the control offspring and 46/46 (100%) of the treatment offspring had normal FBG (FBG < 5.7 mmol/l). Twenty-five of 25 (100%) of control and 42/46 (91.3%) of the treatment offspring had normal glucose tolerance (2hGTT < 7.8 mmol/l) (% difference 8.7, 95% CI -5.6, 20.3). BMI < 85th percentile was found in 25/33 (75.8%) of the treatment group and 44/52 (84.6%) of the control group (difference in percentage -8.9, 95% CI -27.2, 7.8).

Conclusions: School-age children of mothers with GDM are at risk of IGT and overweight, even if from a low-risk ethnic population. FBG was not adequate for screening this population. Minimal intervention for glycaemic control in GDM pregnancies appears to be as effective as tight control for preventing IGT in childhood but not for preventing obesity.