Following the publication of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study, 1 the International Association of Diabetes in Pregnancy Study Groups (IADPSG) 2 formulated consensus guidelines for the testing and diagnosis of gestational diabetes mellitus (GDM). These have been adopted by the American Diabetes Association (ADA). 3 The Ministry of Health (MOH) of China also recommended new testing and diagnostic criteria based on the IADPSG guidelines 4 , which became effective on December 1, 2011. The Chinese criteria agree with the ADA in 2013 that a diagnostic 75 g oral glucose tolerance test (OGTT) should be performed between the 24th and 28th weeks of gestation for all pregnant women not previously known to have diabetes. A diagnosis of GDM can be made if one or more of the following glucose levels are elevated: fasting ≥5.1 mmol/L, 1-hour ≥10.0 mmol/L, and 2-hour ≥8.5 mmol/L.