Abstract:
Background: Gestational diabetes mellitus (GDM) is a major public health problem associated with increased perinatal morbidity and later metabolic disease, both for the mother and offspring. However, the detection thresholds for GDM are widely debated. The International Association of Diabetes in Pregnancy Study Groups (IADPSG) has recommended lower detection thresholds than currently used in New Zealand (NZ) based on epidemiological evidence showing a continuous association between increasing maternal dysglycaemia and risk of adverse perinatal outcomes. Use of these lower criteria would increase the GDM incidence at least two-fold, but there is currently no clinical trial evidence that detecting and treating milder forms of GDM has clinical benefit.
Aim: To assess the effect of detection and treatment of GDM using the lower IADPSG criteria and higher current NZ criteria on infant growth and nutrition in the BabyGEMS Study.
Methods: BabyGEMS Study is a prospective infant cohort study nested within the Gestational Diabetes Mellitus Study of Diagnostic Thresholds (GEMS) Trial, a two-arm, parallel, double-blind randomised trial comparing the effect of diagnosing GDM with lower IADPSG with higher current NZ criteria in a one-step approach. BabyGEMS includes a random 5% sample of control infants not exposed to GDM and three infant GDM exposure groups: A) mild treated GDM by IAPSG criteria; B) mild untreated GDM by IADPSG criteria; and C) treated GDM by current NZ criteria. Infants were assessed for anthropometry and air displacement plethysmography at birth and 6 months’ corrected age, and parents completed surveys about feeding, nutrition and appetitive traits. The primary outcome was whole-body fat mass at 6 months.
Results: 760 infants were included the BabyGEMS Study. Compared to control infants, GDM exposure groups had similar body size and composition at birth and 6 months. Infants exposed to mild treated GDM had a modest increase in the rate of exclusive breastfeeding at ≥5 months but no other benefits were identified relating to infant feeding and nutrition, including energy intake.
Conclusion: There are no clear benefits of treating mild GDM on infant growth and nutrition. Until maternal or infant benefit is demonstrated, clinicians should continue to use current NZ criteria to diagnose women with GDM.