Early Diagnosed Gestational Diabetes Mellitus Is Associated With Adverse Pregnancy Outcomes: A Prospective Cohort Study

Context The significance of an early diagnosis of gestational diabetes mellitus (GDM) with oral glucose tolerance test (OGTT) has not been determined. Objective The objective of this work is to investigate GDM diagnosed by early and standard OGTTs and determine adverse maternal and neonatal outcomes associated with early GDM diagnosis. Research Design and Methods The Early Diagnosis of Gestational Diabetes Mellitus study is a prospective cohort study. Each participant in the study underwent 2 OGTTs, an early OGTT at 18 to 20 gestational weeks (gws) and a standard OGTT at 24 to 28 gws. The reproduciblity between early and standard OGTT were analyzed. Maternal and neonatal metabolic disorders and pregnancy outcomes were compared across groups. Results A total of 522 participants completed both the early and standard OGTTs. The glucose values in the early OGTT were not significantly different from those in the standard OGTT (fasting: 4.31 ± 0.41 mmol/L vs 4.29 ± 0.37 mmol/L, P = .360; 1-hour: 7.68 ± 1.71 mmol/L vs 7.66 ± 1.59 mmol/L, P = .826; 2-hour: 6.69 ± 1.47 mmol/L vs 6.71 ± 1.39 mmol/L, P = .800). The reproducibility of early and standard OGTT results was 74.9%. Pregnant women in the GDM group had higher glycated hemoglobin, C-peptide, and homeostasis model assessment of insulin resistance in the late gestational period. Neonates born to mothers in the GDM group were at a higher risk of being large for gestational age (odds ratio [OR]: 3.665; 95% CI, 1.006-11.91) and were also more prone to neonatal hyperinsulinemia (OR: 3.652; 95% CI, 1.152-10.533). Conclusion Early-onset GDM diagnosed by OGTT at 18 to 20 gws is associated with maternal and neonatal metabolic disorders and adverse pregnancy outcomes. Further randomized controlled trials on the therapeutic efficacy for early-onset GDM will confirm the significance of early screening for GDM.