Abstract
Introduction and Objective: The optimal glucose targets in gestational diabetes mellitus (GDM) remains unknown. This study aimed to investigate the threshold of hyperglycemia associated with adverse outcomes in GDM using continuous glucose monitoring (CGM). Methods: This prospective cohort study recruited a total of 717 singleton pregnant women with GDM performing CGM during pregnancy. Time above ranges (TARs) were calculated as the percentage of time above the glucose thresholds from 5.6 to 8.1 mmol/L (100 to 145 mg/dl, increase by 5mg/dl each) during the whole CGM period respectively. Multivariate logistic regression analysis and restricted cubic spline (RCS) curve analysis were employed to explore the optimal threshold and range of TAR. Results: Of the 717 GDM women, 172 (24.0%) had LGA infants, and 144 (20.1%) had composite adverse outcomes. Only TARs with a threshold of 6.9 mmol/L (TAR>6.9) or above were significantly associated with the risk of LGA after adjusting confounders. For per absolute 5% increase in TAR>6.9, the risk of LGA was increased by 9.8% (OR 1.098, 95% CI: 1.008, 1.195). RCS curve showed that when TAR>6.9 > 26.0%, the risk of LGA increases with elevating TAR>6.9. Conclusion: A glucose level exceeding 6.9 mmol/L and TAR>6.9 > 26.0% were significantly associated with higher risk of LGA in women with GDM. Strict glycemic control may result in better prognoses.