Continuous glucose monitoring to find high blood sugar early in pregnancy

Who can take part

• Maternal age of 18 years and older
• Singleton pregnancy
• Gestational age up to 14w 6d of pregnancy, determined on ultrasound, for initiation of screening; Although it is preferable that ultrasound results be available prior to enrollment, if ultrasound results are not available at the time of enrollment, participant can have CGM initiated but will be dropped if not eligible after results are available
• HbA1c <6.5% (48 mmol/mol) since onset of pregnancy; If HbA1c result not available at time of enrollment, participant can have blinded screening CGM initiated, but results will be needed prior to randomization to verify eligibility
• No prior history of gestational diabetes mellitus (GDM)
• Able to read English or Spanish

Who cannot take part

• Prior gastric bypass surgery
• Use of corticosteroids by a route that can produce hyperglycemia (e.g., oral, intravenous, intramuscular, intra-articular) during the 7 days prior to initiating CGM screening or during the CGM screening; Topical and inhaled corticosteroids are acceptable
• Use of insulin during the pregnancy prior to enrollment
• Pregravid diabetes (type 1 or type 2)
• Use of metformin within one week of the initiation of the blinded CGM sensor for screening or use of a GLP-1 or other weight-reduction medication that can affect glucose levels within 4 weeks of the initiation of the blinded CGM sensor for screening
• Screening CGM meeting study criteria for hyperglycemia: 5% to <25% time >140 mg/dL
• Signs of abnormal fetal or placental development (suspected fetal anomaly or placenta accreta spectrum, low PAPPA) at first routine prenatal visit/ultrasound
• Planned termination of pregnancy or any indications of miscarriage
• Unwillingness/inability to wear CGM sensor
• Unwillingness to attend routine antenatal obstetric appointments
• Deemed unable to participate for medical reasons identified by their physician; Additional Criteria for RCT Eligibility
• Randomization by 16 week 6 days of pregnancy
• No participation in a separate intervention trial