CGM Adherence Compared to Finger-stick Glucose Monitoring in Pregnancies With Type 2 Pregestational Diabetes

About 1-2% of pregnant patients in the United States have pregestational type 2 diabetes (T2DM). The current standard of care for patients needing pharmacotherapy is to initiate basal and postprandial insulin as determined by the patient's reported blood glucose levels after a week of finger-stick glucose monitoring (FSG). This approach is dependent on the patient performing four finger sticks daily and keeping a record of those values. Titration of medication is also dependent on this process. Patient adherence with finger stick glucose testing is reported at about 50%. Continuous glucose monitors (CGMs) allow for continuous collection of blood glucose data without the patient needing to stick themselves or record their values. Increased adherence has been associated with improved maternal and neonatal outcomes. The goal of this randomized control trial is to determine if CGMs have greater adherence compared to FSG. The investigator's first aim is to compare adherence to glucose monitoring using CGM versus finger stick monitoring in pregnant patients with T2DM. The investigator's second aim is to compare neonatal and maternal outcomes using CGM versus finger stick monitoring in pregnant patients with T2DM. The investigators hypothesize that CGMs will have increased adherence compared to finger stick glucose monitoring. The investigators also hypothesize that CGM will lead to improved glycemic control, improved neonatal outcomes, and improved maternal outcomes compared to finger stick glucose monitoring. This is a prospective randomized controlled trial (RCT) comparing adherence to CGM versus FSG in patients with pregestational T2DM prior to initiating prenatal care. T2DM will be defined as the American Diabetes Association (ADA) criteria for diagnosis prior to the date of conception. Patients will receive a CGM after diagnosis will target blood glucose ranges between 65-140 mg/dL. Participants will be screened, consented, and recruited at their initial prenatal visit. They will then be randomized to either the control FSG arm or the intervention CGM arm. Patients with T2DM are seen every 1 to 2 weeks for medication titration and BG checks, and the investigators would continue this workflow, following patients to delivery. If the patient requires insulin uptitration, a weight-based regimen as described by the ADA will be used. Patients will be seen every 1-2 weeks to titrate insulin to meet target ranges. The only difference in management between two groups will be the way the investigators measure blood glucose. Any indications for delivery will be managed in the same manner independent of group assignment based on the institution's clinical guidelines. After delivery, the investigators would review the documented neonatal and maternal outcomes and documented adherence. The primary outcome is percent adherence, which will be calculated as number of days used with \>75% of time coverage divided by the number of days from initiation to delivery for CGM and number of values reported divided by 28 (4 values are intended to be reported daily), divided by weeks from initiation to delivery for FSG. Secondary outcome is a composite of adverse neonatal outcomes, including the following measures: stillbirth, miscarriage, large for gestational age (LGA) of neonate defined as birth weight \>90th percentile for gestational age, fetal hypoglycemia defined as glucose \<40 mg/dL \<48 hours after birth or glucose, hyperbilirubinemia, stillbirth or neonatal death, or birth trauma. Another secondary outcome is a composite of adverse maternal outcomes, including the following measures: maternal hypoglycemia \< 60 mg/dL, shoulder dystocia, OASIS Injuries, operative delivery or c-section, postpartum hemorrhage, or hypertensive disorder of pregnancy.