Diabetes in pregnancy: glycemia control guidelines and rationale

Little consensus exists on the definition of gestational diabetes (GDM), how the condition should be diagnosed, and if interventions for mild maternal hyperglycemia are of any benefit to the mother or fetus. Today, after several large multicenter clinical trials, we are closer than ever to a national and international consensus.

Glucose tolerance in pregnancy is a continuum, which has a fundamental link to fetal growth. The relationship between maternal glycemia and adverse outcomes is continuous, with no distinct inflection point for increased risk. As a result, any cut-off for the diagnosis of GDM is somewhat arbitrary. Treatment for GDM, even mild cases, significantly reduces the rate of certain adverse perinatal and maternal outcomes, warranting intervention.

Clinical guidelines for the diagnosis of GDM are expected to change in the near future provided that recommendations from the International Association of Diabetes and Pregnancy Study Group are accepted by professional organizations. The criteria for the diagnosis will likely be based on a single 75 g, 2-h oral glucose tolerance test with at least one abnormal value. The proposed threshold values are based on an international consensus regarding risk of adverse pregnancy outcomes. The public health implications for these changes are anticipated to be significant.