Gestational Diabetes: Insulin or Oral Hypoglycemic Agents?

Insulins most commonly used during pregnancy by our group are rapid acting insulins and long acting human insulins (long acting analogs are not authorized in pregnancy). An ultra-fast acting insulin will be started before a meal (1, 2 or 3 meals) at 4-6 IU (according to the weight) if the glycemic value 2 hours after this meal is ≥ 6.7 mmol/L in 50% of cases. It will be increased by 2 units every 2 days until obtaining the aimed objectives. Long acting insulin will be started at 4-6 units at bedtime if the glycemic value before breakfast is ≥ 5.3 mmol/L in 50% of cases, and it will be increased by 2 units every 2 days until reaching the objective. A combination of both insulins could be necessary (maximum of 4 injections per day).

Metformin (tablets of 500 mg) will be started at 250 mg/day x 1 day, and increased thereafter by 250 mg per day every 3 days until obtaining an adequate glycemic control. If metformin does not prove its effect at a dose of 750 mg, or if the side effects (mainly gastric) command to slow down or not to increase the posology, glyburide will be added. Glyburide (tablets of 5 mg) will be started at a dose of 2.5 mg and will be increased by 2.5 mg every 3 days until obtaining an adequate glycemic control. The maximal dose in the study will bw 10 mg. It corresponds to the half of the maximal dose recommended in Canada. Treatment failure is defined as glycemia above the Canadian Diabetes Association therapeutic objectives in spite of maximal doses or whether the doses can not be increased because of side effects. Insulin will be added to oral hypoglycemic agents.