Efficacy of FGM in Pregestational Diabetes

Specific Aims Aim 1: To compare the glycemic control and glucose variability during pregnancy and at first postpartum visit in the two randomized groups. This was accomplished by the evaluation of the mean glycated hemoglobin (HbA1c) levels and of several glucose variability indices during gestation and 1 month after delivery. Hypothesis: the real-time information provided by the FGM system improves glucose control and glycemic excursions during pregnancy and after delivery.

Aim 2: To compare the maternal and neonatal adverse outcomes in the two randomized groups at the time of delivery. This was accomplished by the evaluation of the rate of all the most important maternal and fetal-neonatal adverse outcomes (e.g. cesarean section, macrosomia, neonatal hypoglycemia) at the end of gestation. Hypothesis: the use of FGM reduces the rates of those adverse pregnancy outcomes related to maternal hyperglycemia.

Significance and Background Pre-gestational diabetes is still associated with adverse perinatal outcomes largely attributed to maternal hyperglycemia. The risk of adverse outcomes increases with HbA1c higher than 6-6.5% during gestation. Conversely, mean HbA1c levels <6% during the second and third trimester are associated with better outcomes and with the lowest risk of large-forgestational-age infants. Unfortunately, this goal is often difficult to achieve during pregnancy considering that approximately 60% of all pre-gestational diabetic women are poorly controlled at the time of conception and that maternal hypoglycemia should be avoided. Fasting and post-prandial SMBG are recommended in pre-gestational diabetic women to achieve glycemic control during gestation. Additional useful information on direction, frequency and duration of glycemic oscillations could be provided by the CGM. This system, in fact, allows the patients to prevent hypoglycemia and to reduce glucose oscillations measuring interstitial glucose levels continuously. Despite initial controversial results on the efficacy of the CGM technology during pregnancy, a recently published trial demonstrated that Real-Time use of CGM is associated with improved neonatal outcomes (which are likely to be attributed to reduced exposure to maternal hyperglycemia).

Unfortunately the existing CGM devices still need to be frequently calibrated, using a minimum of 2-5 daily monitored capillary blood glucose. The recent introduction of FGM using the factory-calibrated meter has emerged as a novel method to study glycemic patterns. FGM does not require finger prick calibration. The data are extrapolated using the inbuilt software to summarize the glycemic variability over 2 weeks. The glucose profile obtained using this system is called Ambulatory Glucose Profile (AGP). The usefulness of AGP has been studied in adults and pediatric patients affected by diabetes.

Nevertheless, to date there are no studies looking into the efficacy of this tool in women affected by pre-gestational (Type 1 and Type 2) diabetes during pregnancy. The investigators aim to evaluate the effectiveness of antenatal FGM on maternal glycemic control and pregnancy related morbidity in the offspring of mothers with poorly controlled Type 1 and Type 2 diabetes at the time of conception (peri-conception HbA1c ≥6.5%).

Inclusion criteria

• Pregnant women with pregestational diabetes
• HbA1c >6.5%

Exclusion criteria

• Gestational Diabetes
• HbA1c <6.5%