Reassessment of the new diagnostic thresholds for gestational diabetes mellitus: an opportunity for improvement

In reply: Callaway and McElduff are dismissive of the concerns I raised in my recent article,1 asserting incorrectly that they are old arguments. The potential reduction of the risk of macrosomia (birthweight > 90th centile; large for gestational age babies) when one or more blood glucose levels (BGLs) on an oral glucose tolerance test are normal was only suggested recently, in February 2014.2 In response, new data3 confirmed the statistical flaw in the new diagnostic criteria for gestational diabetes mellitus (GDM). These data showed that (i) nearly 50% of women having only one elevated BGL test result do not reach the diagnostic risk threshold, and (ii) women having two or more BGL results just below the new diagnostic levels may be at greater risk, yet will not be identified.1