The Australasian Diabetes in Pregnancy Society recommends high-risk screening women for GDM before 24 weeks gestation, assuming that an earlier diagnosis and opportunity to achieve normoglycemia will minimize adverse outcomes. However, little evidence exists for this recommendation. The study objective was to compare the pregnancy outcomes of high-risk women diagnosed with GDM before 24 weeks gestation and routinely analyzed women after 24 weeks gestation. Researchers conducted a retrospective audit of all pregnancies diagnosed with GDM using the International Association of Diabetes and Pregnancy Study Groups criteria over 12 months at an Australian tertiary hospital. Researchers compared adverse perinatal outcomes between “Early GDM” diagnosed before 24 weeks and “Late GDM” analyzed 24 weeks. Early GDM had a significantly lower newborn composite outcome frequency than Late GDM. Primary cesarean, hypertensive disorders, postpartum hemorrhage, birth weight >90th percentile, macrosomia, and preterm birth frequencies were not significantly different. Therefore, high-risk women diagnosed with GDM in early pregnancy were not more likely to have an adverse outcome than routinely analyzed women. As they are a high-risk group, this may indicate a possible benefit to the early diagnosis of GDM.