One vs Two Step Approach for GDM Screening

Gestational Diabetes is screened for in pregnancy by drinking a solution containing a certain amount of glucose and testing blood glucose level one hour after drinking it. If this value is above a certain cut-off (>135mg/dl), the patient is subjected to another test involving drinking a solution containing a higher amount of glucose and checking blood glucose while fasting, 1 hour after drinking the solution and 2 hours after drinking the solution. (Two step approach).

Cut off values will be: 3 hour>180 mg/dl, 2 hour > 155 mg/dl, 1hour >140 mg/dl, fasting >95mg/dl. Two abnormal values will meet the diagnosis of gestational diabetes.

In other parts of the United States, and most of the rest of the word, screening for gestational diabetes uses a one-step approach by drinking a solution containing 75g of glucose (As recommended by the American Diabetic Society, the Endocrine Society, WHO and the International Association of Diabetes and Pregnancy Study groups1-3). Blood glucose values are checked at fasting, one hour and two hours after solution drinking.

The diagnosis of gestational diabetes is based on one elevated values. (cut off: Fasting ≥92mg/dl, 1hour ≥180 mg/dl, 2 hours ≥153 mg/dl).

Our study will assess if there is a difference in incidence of gestational diabetes using these different screening approaches. Prior studies have proven similar incidences including a randomized controlled trial.