In the two-step approach for diagnosing GDM, what is the first step?

The first step in the two-step approach for diagnosing Gestational Diabetes Mellitus (GDM) is to administer a 1-hour 50 g glucose load. This initial screening test, often referred to as the glucose challenge test, is non-fasting and involves giving the pregnant individual a sweet glucose solution. After one hour, blood glucose levels are measured to determine if further testing is needed.

If the screening test shows elevated glucose levels, a follow-up diagnostic test, typically the 100 g Oral Glucose Tolerance Test (OGTT), is then performed to confirm the diagnosis of GDM. This two-step approach effectively identifies individuals who may require further evaluation and intervention. The initial screening with the 50 g glucose load is preferable because it is simple to perform, does not require fasting, and allows for a quick assessment of glucose metabolism in pregnancy.