The recommended first-line treatment for women with gestational diabetes mellitus (GDM) in the case of failure of diet is insulin. Recent results suggest that there is a potential role for glyburide therapy and highlight the need for better knowledge of glycaemic control with glyburide. The objective of this study was to describe and quantify in women with GDM the quality of glycaemic control, including the risk of maternal hypoglycaemia and of therapy failure.

This is a secondary analysis of the French INDAO non-inferiority trial from 2012 to 2016, in which 890 women with GDM randomized to receive glyburide or insulin treatment were compared for perinatal outcomes. Blood glucose concentrations were assessed prospectively during pregnancy. Optimal glycaemic control was defined as less than 20% of blood glucose values exceeding the targets.

More than 50% of the women had optimal glycaemic control with glyburide, similar to that with insulin. Around 40% of the women had at least one episode of hypoglycaemia, more than with insulin. However, those hypoglycaemic episodes were mostly moderate and the rate of severe hypoglycaemia decreased significantly during the course of the trial.

Failure of glyburide treatment (switch to insulin therapy) occurred in 18% of women and had few predictors. However, when failure occurred, glycaemic control was improved after switching to insulin.

Glyburide is an effective treatment for reaching glycaemic goals during pregnancy in women with GDM. The risk of maternal hypoglycaemia may be minimized by clinical practice experience. These findings could be taken into account in the management of GDM.