Powe et al described variable “defects” (defined as parameter values <25th centile for non GDMs) in OGTT derived insulin secretion (Isecr) and sensitivity (Isens) estimates in GDM. They reported that pregnancy complications relate primarily to low Isens. To explore applicability to routine OGTT data, an analogous but simplified analysis was undertaken, classifying IADPSG GDM women according to FVPG < or ≥ 75th centile for non GDM women (cut-off 4.6 mmol/L - near the cohort mean (SD) of 4.5(0.4) mmol/L). Our multi-ethnic cohort included a diverse group of 6128 untreated women from 5 centers in the blinded epidemiologic HAPO study. Analyses compared outcome frequencies (LGA, excess neonatal (NN) adiposity, NN hypoglycemia, NN hyperinsulinemia, preterm birth, primary C section) with non GDM women and between GDM-FVPG groups using χ2 tests and logistic regression analyses adjusted for maternal age, height, smoking, FH diabetes, BMI at OGTT visit and ethnicity (Table 1). The 25% of GDM women with FVPG < 4.6 mmol/L were at much lower risk of adverse outcomes. Although “mechanistic” classification considering Isecr and Isens may offer insights for treatment, a simpler classification by FVPG performs better and appears simpler for routine use. A modified “two-step” approach for detection and classification of pregnancy hyperglycemia, using FVPG as the first step, deserves consideration.

D. McIntyre: None. K.S. Gibbons: None. L.R. Madsen: None. R.C. Ma: Advisory Panel; Self; Boehringer Ingelheim International GmbH. Research Support; Self; AstraZeneca, Bayer AG, Pfizer Inc. Stock/Shareholder; Self; GemVCare. Other Relationship; Self; AstraZeneca. D.A. Sacks: None. W.H. Tam: None. P. Catalano: None.


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