The diagnosis of gestational diabetes has been based for decades either, in criteria to predict the mother's risk of developing type 2 diabetes in the future, or those used for non -pregnant women.

But gestational diabetes also implies a risk for the baby.In addition, it is still clear from what level maternal blood glucose implies risk to the fetus.

The expert opinions about when to perform reviews to detect gestational diabetes are divided: while some believe that mild hyperglycemia increases the risk to baby's health, others claim that these slight elevations of blood glucose would not have adverse effects, and that they shouldabandon systematic efforts by diagnosing gestational diabetes.

The HAPO study was designed to answer the question of whether an intolerance to glucose by the mother who does not cross the thresholds established for the diagnosis of diabetes implies some risk of adverse results for the baby.