Continuous Glucose Monitoring (CGM) Substudy of the DECIDE RCT

Percent of glycemic variability calculated as the standard deviation (SD) of glucose values divided by the mean glucose in the same observation period, continuous measure

Percent of CGM readings and time below the target glucose range of <63 mg/dL, continuous measure

Percent of CGM readings and time above the target glucose range of >140 mg/dL, continuous measure

LGA will be defined as a birthweight ≥90th%tile for gestational age based on a US birth certificate reference adjusted for parity and/or fetal sex.

Neonatal hypoglycemia will be defined as a blood glucose <35 mg/dL or treatment <24 hours after birth with either IV, PO, or gel glucose therapy.

Neonatal hyperbilirubinemia will be defined as treated with phototherapy or exchange transfusion in the first postnatal week and either treatment in the first postnatal week or kernicterus.

HDP will include either gestational hypertension or preeclampsia. Gestational hypertension will be defined as: systolic blood pressure of 140 mm Hg or more or diastolic blood pressure of 90 mm Hg or more on two occasions at least 4 hours apart after 20 weeks of gestation in a woman with a previously normal blood pressure. Preeclampsia will be defined as: above blood pressure criteria AND proteinuria (300 mg or more per 24 hour urine collection, protein/creatinine ratio of 0.3 mg/dL or more, or dipstick reading of 2+) OR thrombocytopenia (platelet count less than 100 109/L), renal insufficiency (serum creatinine greater than 1.1 mg/dL or a doubling of the serum creatinine concentration in the absence of other renal disease), impaired liver function (elevated blood concentrations of liver transaminases to twice normal concentration), pulmonary edema, new-onset headache or visual symptoms not attributed to other diagnoses.

Preterm birth <37 weeks and <34 weeks based on project gestational age.

Intubation, continuous positive airway pressure (CPAP) or high-flow nasal cannula (HFNC) for ventilation or cardiopulmonary resuscitation within first 72 hours of birth.

Admitted to NICU or intermediate nursery ≥72 hours, any indication.

Requiring oxygen support.

Signs of respiratory distress with oxygen requirement and confirmed by chest x-ray.

Insulin use among individuals randomized to metformin between randomization and delivery.

A1c > 6.5% OR fasting plasma glucose > 126 mg/dL OR OGTT > 200 mg/dL OR prior diagnosis per patient report.

A1c 5.7% to 6.4% OR fasting plasma glucose 100 mg/dl to 125 mg/dL OR OGTT 140 to 199 mg/dL.

OGTT 2-hour value of 140 to 199 mg/dL32

OGTT value of 100 to 125 mg/dL.

Weight and height will be combined to report BMI in kg/m^2. BMI per the following classifications will be assessed: Normal or underweight: < 25 kg/m2; Overweight: 25 to < 30 kg/m2; Class 1: 30 to < 35 kg/m2; Class 2: 35 to < 40 kg/m2; and Class 3: 40 kg/m2 or greater.

Per American Heart Association criteria as below and/or antihypertensive medication or prior diagnosis per patient report, and defined as: Elevated: Systolic between 120-129 and diastolic less than 80 mm Hg; Stage 1: Systolic between 130-139 or diastolic between 80-89 mm Hg; and Stage 2: Systolic at least 140 or diastolic at least 90 mm Hg.

Fasting state, defined as a continuous measure and dichotomous at the following thresholds for each component: Total cholesterol: > 200 mg/dL; LDL cholesterol: > mg/dL; HDL cholesterol: < 40 mg/dL; Triglycerides: > 200 mg/dL.

Mean glucose in mg/dL per CGM readings, continuous measure