How should we screen for gestational diabetes?

Regarding the various aspects of screening strategies for gestational diabetes mellitus (GDM) and to express important conclusions, the recent literature in the field is reviewed. There are no randomized controlled trials examining the effects of different screening methods on health outcomes. Only few studies investigated the new screening strategies. There is an agreement that universal GDM screening is cost-effective. Several professional societies changed their own guidelines recommending universal GDM screening. Currently, the American College of Obstetricians and Gynecologists, the Society of Obstetricians and Gynaecologists of Canada, and the U.K. National Institute for Health and Clinical Excellence recommend routine risk-factor-based screening, whereas the Canadian Diabetes Association, Australasian Diabetes in Pregnancy Society, U.S. Preventive Services Task Force, and ATLANTIC Diabetes in Pregnancy recommend that all asymptomatic women should be screened at 24-28 weeks' gestation. The American Diabetes Association recommends screening all women with a 75-g 2-h oral glucose tolerance test (oGTT). The International Association of Diabetes and Pregnancy Study Groups recommend no glucose challenge test, but proposed new screening criteria introducing fasting glucose levels less than 5.1 mmol/l. There is more and more evidence in the recent literature that GDM screening should be universally performed at 24-28 gestational weeks and followed by definitive testing in women who are labeled as high-risk population. Logically, the best strategy would be connecting the screening with diagnosing GDM in the same procedure using a 75-g oGTT, which should be evaluated. General consensus is about measuring plasma glucose to detect pregestational diabetes in high-risk populations by early testing before 20 weeks of gestation.