DiagnosisGDM carries risks for the mother and neonate.Not all adverse outcomes are ofequal clinical importance. The Hyperglycemiaand Adverse Pregnancy Outcome(HAPO) study (62), a large-scale multinationalcohort study completed by morethan 23,000 pregnant women, demonstratedthat risk of adverse maternal, fetal,and neonatal outcomes continuouslyincreased as a function ofmaternal glycemiaat 24–28 weeks of gestation, evenwithin ranges previously considered normalfor pregnancy. Formost complications,there was no threshold for risk. These resultshave led to careful reconsideration ofthe diagnostic criteria for GDM. GDM diagnosis(Table 2.6) can be accomplishedwith either of two strategies:1. “One-step” 75-g OGTT or2. “Two-step” approach with a 50-g (nonfasting)screen followed by a 100-gOGTT for those who screen positiveDifferent diagnostic criteria will identifydifferent degrees of maternal hyperglycemiaand maternal/fetal risk, leadingsome experts to debate, and disagree on,optimal strategies for the diagnosis ofGDM.