Purpose: This retrospective cohort study aims to investigate whether high-normal fasting blood glucose (FBG) affects assisted reproductive technology (ART) outcomes undergoing single blastocyst frozen-thawed embryo transfer (FET) cycles in women with normal body mass index (BMI).944 women with normal BMI and FBG levels undergoing single blastocyst FET cycles were enrolled. Based on the median of FBG (4.97 mmol/L, 1 mmol/L = 18 mg/dL), the subjects were categorized into the low-normal group (3.90 ≤ FBG ≤ 4.97 mmol/L, n = 472) and the high-normal group (4.97 < FBG < 6.10 mmol/L, n = 472). Multivariable logistic regression and receiver operating characteristic (ROC) were used to analyze the relationship between high-normal FBG and ART outcomes. Primary outcome: live birth rate (LBR).LBR was significantly lower in the high-normal group than in the low-normal group (36.8% vs. 45.1%, p = 0.010), and the miscarriage rate was considerably higher than that in the low-normal group (23.9% vs. 16.5%, p = 0.041). High-normal FBG of female was an independent predictor of live birth (adjusted OR:0.747, 95% CI: 0.541–0.963, p = 0.027) and miscarriage (adjusted OR:1.610, 95% CI: 1.018–2.547, p = 0.042). ROC analyses showed that the cut-off values of FBG (endpoints: live birth and miscarriage) were 5.07 mmol/L, and 5.01 mmol/L, respectively.In women with normal BMI, high-normal FBG is an independent risk factor for lower LBR and higher miscarriage rate in single blastocyst FET cycles. Attention to preconception FBG monitoring in this particular population may allow early intervention to improve ART outcomes.Methods: This retrospective cohort study aims to investigate whether high-normal fasting blood glucose (FBG) affects assisted reproductive technology (ART) outcomes undergoing single blastocyst frozen-thawed embryo transfer (FET) cycles in women with normal body mass index (BMI).944 women with normal BMI and FBG levels undergoing single blastocyst FET cycles were enrolled. Based on the median of FBG (4.97 mmol/L, 1 mmol/L = 18 mg/dL), the subjects were categorized into the low-normal group (3.90 ≤ FBG ≤ 4.97 mmol/L, n = 472) and the high-normal group (4.97 < FBG < 6.10 mmol/L, n = 472). Multivariable logistic regression and receiver operating characteristic (ROC) were used to analyze the relationship between high-normal FBG and ART outcomes. Primary outcome: live birth rate (LBR).LBR was significantly lower in the high-normal group than in the low-normal group (36.8% vs. 45.1%, p = 0.010), and the miscarriage rate was considerably higher than that in the low-normal group (23.9% vs. 16.5%, p = 0.041). High-normal FBG of female was an independent predictor of live birth (adjusted OR:0.747, 95% CI: 0.541–0.963, p = 0.027) and miscarriage (adjusted OR:1.610, 95% CI: 1.018–2.547, p = 0.042). ROC analyses showed that the cut-off values of FBG (endpoints: live birth and miscarriage) were 5.07 mmol/L, and 5.01 mmol/L, respectively.In women with normal BMI, high-normal FBG is an independent risk factor for lower LBR and higher miscarriage rate in single blastocyst FET cycles. Attention to preconception FBG monitoring in this particular population may allow early intervention to improve ART outcomes.Results: This retrospective cohort study aims to investigate whether high-normal fasting blood glucose (FBG) affects assisted reproductive technology (ART) outcomes undergoing single blastocyst frozen-thawed embryo transfer (FET) cycles in women with normal body mass index (BMI).944 women with normal BMI and FBG levels undergoing single blastocyst FET cycles were enrolled. Based on the median of FBG (4.97 mmol/L, 1 mmol/L = 18 mg/dL), the subjects were categorized into the low-normal group (3.90 ≤ FBG ≤ 4.97 mmol/L, n = 472) and the high-normal group (4.97 < FBG < 6.10 mmol/L, n = 472). Multivariable logistic regression and receiver operating characteristic (ROC) were used to analyze the relationship between high-normal FBG and ART outcomes. Primary outcome: live birth rate (LBR).LBR was significantly lower in the high-normal group than in the low-normal group (36.8% vs. 45.1%, p = 0.010), and the miscarriage rate was considerably higher than that in the low-normal group (23.9% vs. 16.5%, p = 0.041). High-normal FBG of female was an independent predictor of live birth (adjusted OR:0.747, 95% CI: 0.541–0.963, p = 0.027) and miscarriage (adjusted OR:1.610, 95% CI: 1.018–2.547, p = 0.042). ROC analyses showed that the cut-off values of FBG (endpoints: live birth and miscarriage) were 5.07 mmol/L, and 5.01 mmol/L, respectively.In women with normal BMI, high-normal FBG is an independent risk factor for lower LBR and higher miscarriage rate in single blastocyst FET cycles. Attention to preconception FBG monitoring in this particular population may allow early intervention to improve ART outcomes.Conclusions: This retrospective cohort study aims to investigate whether high-normal fasting blood glucose (FBG) affects assisted reproductive technology (ART) outcomes undergoing single blastocyst frozen-thawed embryo transfer (FET) cycles in women with normal body mass index (BMI).944 women with normal BMI and FBG levels undergoing single blastocyst FET cycles were enrolled. Based on the median of FBG (4.97 mmol/L, 1 mmol/L = 18 mg/dL), the subjects were categorized into the low-normal group (3.90 ≤ FBG ≤ 4.97 mmol/L, n = 472) and the high-normal group (4.97 < FBG < 6.10 mmol/L, n = 472). Multivariable logistic regression and receiver operating characteristic (ROC) were used to analyze the relationship between high-normal FBG and ART outcomes. Primary outcome: live birth rate (LBR).LBR was significantly lower in the high-normal group than in the low-normal group (36.8% vs. 45.1%, p = 0.010), and the miscarriage rate was considerably higher than that in the low-normal group (23.9% vs. 16.5%, p = 0.041). High-normal FBG of female was an independent predictor of live birth (adjusted OR:0.747, 95% CI: 0.541–0.963, p = 0.027) and miscarriage (adjusted OR:1.610, 95% CI: 1.018–2.547, p = 0.042). ROC analyses showed that the cut-off values of FBG (endpoints: live birth and miscarriage) were 5.07 mmol/L, and 5.01 mmol/L, respectively.In women with normal BMI, high-normal FBG is an independent risk factor for lower LBR and higher miscarriage rate in single blastocyst FET cycles. Attention to preconception FBG monitoring in this particular population may allow early intervention to improve ART outcomes. [ABSTRACT FROM AUTHOR]