Optimal glycemic control during pregnancy in type 1 diabetic (T1D) women is essential to prevent maternal and fetal complications. Although continuous glucose monitoring (CGM) help reaching targeted glucose levels (63-140 mg/dl), unfortunately only a minority of T1D women achieves the cumulative recommended time spent in euglycemia [Time In Range (TIR)]>70% during pregnancy. Recently aHCL systems has allowed a significant improvement in glycemic control in T1D patients and more and more frequently T1D women begin pregnancy with this system. The aim of our retrospective, real word study was to evaluate CGM metrics [mean glucose concentration (MGC), standard deviation(SD), TIR, Time Below Range (TBR), Time Above Range (TAR), Coefficient of Variation (CV), Kovatchev indices (HBGI and LBGI), Continuous Overall Net Glycemic Action (CONGA-1,2,4) and J-index] in 14 Caucasian T1D pregnant women (mean age 33.3±4 years, duration of diabetes 19.6±4.5 years, BMI 23.7±3.3 kg/m2, HbA1c 48.6±8.9 mmol/mol) treated with aHCL Minimed 780G system and followed up in Diabetes Unit of Papa Giovanni XXIII Hospital in Bergamo from August 2021 to May 2023.Twelve women were already using aHCL system before pregnancy and all women retained CGM>90% across all trimesters. Target glucose setpoint was set to 100 mg/dl. All women were trained to carbohydrate count. During pregnancy MGC improved significantly from the first to the second trimester (135±9 vs 126±9 mg/dl; p<0.001), TIR increased (58.5% in first, 64.4% in second and 67.6% in third trimester; p<0.05), TAR decreased (39.5% in first, 33.1% in second and 30% in third trimester; p<0.05) as well as CV (from 32.7±3% in second to 30.5±3% in third trimester; p<0.001). A significant progressive decrease of Kovatchev indices, CONGA-1,2,4 and J index was observed in all trimesters of pregnancy (p<0.05). The small sample of pregnant women in this study was unable to establish a possible reduction in obstetric and neonatal outcomes. In conclusion, our data demonstrated that the use of an aHCL system in TD1 women in pregnancy was safe and resulted in a significant increase in pregnancy-specific TIR>9% along with an improvement in all glycemic variability indices. Although we don’t know whether this improvement in glycemic control may determine better maternal and fetal outcomes, however it is possible to speculate that a 5% improvement in TIR could be sufficient to improve pregnancy outcomes, as previous evidence suggest.