This document discusses gestational diabetes mellitus (GDM). It defines GDM as carbohydrate intolerance that is recognized or begins during pregnancy. The document discusses the types, risk factors, pathophysiology, screening recommendations, and classifications of diabetes in pregnancy according to White's groups. It notes that GDM occurs in about 7% of pregnancies globally and prevalence varies between racial/ethnic groups and countries. Screening is recommended between 24-28 weeks of gestation using a 75g oral glucose tolerance test.