Jokelainen M, Stach-Lempinen B, Rönö K, et al. - Researchers examined early-pregnancy oral glucose tolerance test (OGTT) findings as well as disparities between early- and late-pregnancy OGTT findings in a population-based cohort. Participants were pregnant women in South Karelia, Finland, who underwent a 2-hour 75g OGTT at 12-16 weeks’ gestation (OGTT1) and if normal, had repeat examination at 24-28 weeks (OGTT2). Diagnosis of early and late gestational diabetes (GDM) was made employing the same nationally endorsed criteria (fasting [FPG], 1- or 2-hour plasma glucose ≥ 5.3, ≥ 10.0 or ≥ 8.6 mmol/L, respectively). In OGTT1 (n = 1,401), the mean (SD) FPG, 1- and 2-hour values were recorded to be 4.85 (0.34), 6.63 (1.73) and 5.60 (1.28) mmol/L, respectively. A diagnosis of early GDM was made in 209 (14.9%). A diagnosis of late GDM was made in 114 (10.6%) in OGTT2 (n = 1,067). Among females without GDM (n = 953), higher mean FPG values and lower post-load values were seen in OGTT1 compared with OGTT2. In females with late GDM, lower mean FPG and post-load values were detected in OGTT1 vs OGTT2. The use of the IADPSG GDM criteria produced similar results. The necessity to generate gestational-age specific OGTT thresholds for early GDM diagnosis was suggested by the revelations in this study.