Response to Comment on Hughes et al. An Early Pregnancy HbA1c ≥5.9% (41 mmol/mol) Is Optimal for Detecting Diabetes and Identifies Women at Increased Risk of Adverse Pregnancy Outcomes. Diabetes Care 2014;37:2953–2959

We appreciate the opportunity to respond to the comments made by Anderson et al. (1) on our recent article (2). We agree, as highlighted under our study limitations, that the low participation rate in the oral glucose tolerance test (OGTT) could affect the validity of the HbA1c sensitivity and specificity calculations. As women with lower HbA1c (particularly <5.6% [38 mmol/mol]) were least likely to consent to an early OGTT, it is possible that the optimal HbA1c threshold for identifying women with undiagnosed preexisting diabetes (not gestational diabetes mellitus [GDM]) is in fact lower than 5.9% (41 mmol/mol) and we invite others …