Final answer:
Screening for gestational diabetes is recommended during the second trimester of pregnancy, between 24 and 28 weeks. This is because insulin resistance peaks during this period, increasing the risk for gestational diabetes.
Step-by-step explanation:
Pregnant women should be screened for gestational diabetes during the second trimester, specifically between 24 and 28 weeks of pregnancy. Screening during this time is crucial because the physiological demands of pregnancy peak, resulting in increased insulin resistance which can lead to gestational diabetes. The glucose tolerance test is often used as a method for confirming the diagnosis of diabetes mellitus, including gestational diabetes. It is essential to manage blood sugar levels during pregnancy to avoid complications like ketoacidosis, which can occur when the body overproduces ketone bodies due to increased glucose demand, particularly in the third trimester.