Real-time Continuous Glucose Monitoring

Real-time Continuous Glucose Monitoring for the Treatment of Gestational Diabetes: a Randomized Trial

Gestational diabetes (GDM) is a condition of carbohydrate intolerance with onset or first recognition in pregnancy. The prevalence of GDM is as high as 25% in some populations and continues to rise with the increase in obesity and type-2 diabetes. GDM places the pregnancy at great risk to both the mother and the neonate. Recent studies have proven that interventions including dietary and medications lower the risk to the pregnancy. Both the American College of Obstetrics and Gynecology (ACOG) and the American Diabetes Association (ADA) recommend dietary interventions with daily glucose monitoring as the initial treatment of choice. Meanwhile, outside of pregnancy, promising new technologies such as continuous glucose monitors (CGM) are revolutionizing diabetic care. The investigators seek to determine if the constant feedback of a real-time CGM system would improve glycemic control compared to traditional management in GDM

The investigators' proposed study will add new information to the emerging use of CGM in pregnant women with GDM. First, most studies only use CGM for 48 - 72hours at a time, while the investigators will be using CGM for 7 day intervals. Both groups will use the same Enlite sensor (Medtronic). The blinded CGM group will be using the Medtronic iPro2 system (Enlite sensor + transmitter). The real-time CGM group will be using the 530g system (iPro2 (Enlite sensor + transmitter) + inactivated 530g pump set only to display glucose values, no insulin will be administered). This CGM system has been FDA approved to for up to 7 days between sensor changes.26,27 Second, no previous study has used real time CGM in pregnant patients with GDM in the US. The investigators will be the first to describe the use of this technology in this patient population. Third, most of these trials have been performed on populations that are not representative of the investigators' patient population at EVMS. This will be the largest US study of CGM in GDM. Fourth wearable medical and fitness technology is already popular, but as both the technology and the demand continues to grow, it will become the future of diabetes management. Studies have already shown that real time CGM is an effective educational and motivational tool in type-1 and type-2 DM.28,29

The real-time CGM group will be using the 530g system (inactivated 530g insulin pump (no insulin used, only used as display for CGM), Enlite sensor, MiniLink transmitter)

The blinded CGM group will be using the Medtronic iPro2 system (Enlite sensor + iPro2 transmitter). The real-time CGM group will be using the 530g system (inactivated 530g insulin pump (no insulin used, only used as display for CGM), Enlite sensor, MiniLink transmitter)

Mean blood glucose (mg/dL) in the real-time CGM group compared to self-monitoring of blood glucose (SMBG) group during the 4th week of study from data collected on the 6 day of CGM use during that week.

Gestational hypertension (defined as systolic blood pressure > 140 mm Hg or diastolic blood pressure > 90 mmg Hg, on 2 occasions at least 4 hrs apart

Preeclampsia (defined as gestational hypertension plus either new-onset proteinuria (> 300 mg/24 2hrs, protein:creatinine > 0.3 mg/dL), thrombocytopenia (platelet count < 100,000/uL), elevated Aspartate aminotransferase or alanine aminotransferase (> 2x upper limit of normal), renal insufficiency (serum creatinine > 1.1 mg/dL or an unexplained doubling of creatinine), pulmonary edema, or cerebral or visual symptoms

Cesarean delivery (w/ indication: macrosomia, malpresentation, failed induction, fetal distress, failed trial of labor after cesarean, scheduled repeat, other)

Hypoglycemia (yes/no): < 2 hrs after birth and before feeding, defined as < 35mg/dL Hyperbilirubinemia (yes/no): collected 16-36 hrs after birth, defined as > 95% for any given point after birth requiring phototherapy according to American Academy of Pediatrics guidelines Birth trauma (yes/no): brachial plexus injury or clavicular, humeral, or skull fracture Intrauterine fetal demise or neonatal death (yes/no): prior to hospital discharge

Admission to neonatal intensive care unit (yes/no) and length of neonatal intensive care unit stay (days)

Inclusion Criteria: maternal age 18 to 45 singleton gestation gestational age less than 32 weeks gestation at study inclusion BMI less than 45 50g glucose challenge greater than 135 mg/dL 100 g 3 hr oral glucose tolerance test greater than 2 abnormal values using the Carpenter Coustan cut offs (fasting greater than 95 mg/dL, 1 hr greater than 180 mg/dL, 2 hr greater than 155 mg/dL, 3 hr greater than 140 mg/dL) attended the maternal-fetal medicine diabetes education class Exclusion Criteria: maternal age less than18 or greater than 45 multifetal gestation gestational age greater than 32 weeks study inclusion BMI greater than 45 pregestational diabetes gestational diabetes diagnosed before 24 weeks did not attend the diabetes education class known fetal anomaly known fetal aneuploidy required ongoing treatment with medications that can exacerbate hyperglycemia (steroids, hydroxyprogesterone caproate injections (Makena), highly active antiretroviral therapy HIV medications) learning disability concern for non compliance with medical care imminent preterm delivery due to maternal disease or fetal conditions is not willing to wear CGM

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