Maternal and fetal outcomes associated with flash glucose monitoring metrics in women with type 1 diabetes: A cohort study.

OBJECTIVE: To evaluate the association between flash glucose monitoring (FGM) metrics and perinatal outcomes in pregnant women with type 1 diabetes (T1DM). RESEARCH DESIGN AND METHODS: This retrospective cohort study included pregnant women with T1DM who used FGM. The primary outcome was a composite endpoint including fetal or neonatal mortality, large-for-gestational-age (LGA) birth weight, neonatal intensive care unit (NICU) admission, or neonatal hypoglycemia. Glycated hemoglobin (HbA1c) levels were assessed together with time in range (TIR), time below range (TBR), and time above range (TAR) within pregnancy-specific glucose targets, as well as glucose variability. RESULTS: A total of 70 women were included, with a median age of 36 years (IQR, 31-38), body mass index (BMI) 27±5kg/m2, diabetes duration 20±8 years, and pregestational HbA1c 7.3±1.4%. Among them, 21.7% were smokers, 4.5% had hypertension, 10.1% had dyslipidemia, and 41.2% had diabetic retinopathy. Women who experienced the composite endpoint exhibited significantly lower TIR and higher TAR across all trimesters, greater glycemic variability (CV) during the first (1T) and third trimesters (3T), and a higher glucose management indicator (GMI) in the third trimester. Logistic regression analysis showed that a TIR<69.5% during the second trimester (2T) increased the risk of the composite endpoint by 10.56-fold (P=.015). Similarly, CV≥31.85% during the first trimester was associated with a 6.42-fold increased risk (P=.039). A model combining these 2 variables achieved a sensitivity of 94.3% and a specificity of 50%. CONCLUSIONS: Glycemic control assessed through FGM metrics, particularly TIR during the second trimester and CV during the first trimester, is associated with adverse maternal-fetal outcomes in pregnant women with T1DM.