Fasting or 2-hour postprandial plasma glycemic criteria for gestational diabetes mellitus are aassociated with distinct adverse outcomes

Objective We aimed to evaluate the heterogeneity of gestational diabetes mellitus (GDM) patients diagnosed with various screening criteria. Methods We stratified pregnant women using consecutive fasting plasma glucose (FPG) and 2-hour postprandial plasma glucose (2hPPG) intervals of 0.2 mmol/L. The incidence of abnormal neonatal birthweight and birth-related adverse outcomes was compared with that of pregnant women without GDM. Results The study included 39,988 pregnant women (18-45 years, mean [SD], 31.5 [4.7] years) in Ningbo, China. The means (SDs) of FPG and 2hPPG within 24-28 weeks of gestation were 4.5 (0.5) and 6.8 (1.3) mmol/L, respectively. A total of 3025 (7.6%) women had 5.1-6.9 mmol/L FPG and 4560 (11.4%) had 8.5-11.0 mmol/L 2hPPG. The incidence of GDM according to the two combination criteria was 17.3% (6908 cases). The relative risk (RR) for < 10th percentile birthweight (< 10th WT) was 0.82 (95% CI, 0.74-0.91, p < 0.001) by 5.1 mmol/L FPG criterion and 1.14 (95% CI, 1.06-1.23, p < 0.001) by 8.5 mmol/L 2hPPG criterion, while the RRs for > 90th percentile birthweight (> 90th WT) were 1.48 (95% CI, 1.35-1.63, p < 0.001) and 0.95 (95% CI, 0.86-1.04, p = 0.29) according to the corresponding criteria. The FPG criterion was more strongly associated with maternal hypertension than the 2hPPG criterion. Both criteria did not show a distinct association with other composite adverse outcomes. Conclusion High FPG is significantly associated with high birth weight, whereas high 2hPPG is slightly associated with low birth weight. Our findings highlight the heterogeneity of patients with GDM diagnosed by different criteria.