Continuous Glucose Monitoring for Various Degrees of Glucose Intolerance

Study Overview
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Brief Summary
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Diabetes mellitus affects roughly 8% of pregnancies but is associated with significant perinatal and maternal morbidity, with 6% of pregnancies affected by gestational diabetes mellitus (GDM). Best practice guidelines recommend universal screening for gestational diabetes mellitus between 24-28 weeks of pregnancy in all women who do not have a diagnosis of pre-gestational diabetes mellitus. Among high-risk populations, performing an early diabetes screen is suggested at the initiation of prenatal care to evaluate for pre-gestational diabetes mellitus. Prior studies have demonstrated a difference in perinatal outcomes by comparing women with negative screening tests to those who fail a screen but pass a diagnostic test and those who are ultimately diagnosed with GDM. The investigators aim to use continuous glucose monitoring systems to study glycemic control in the early third trimester to further elucidate the differences between pregnant women with euglycemia, glucose intolerance, and GDM.

Official Title
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The Use of Continuous Glucose Monitors Among Women With Various Degrees of Glucose Intolerance: An Observational Cohort Study

Conditions
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Diabetes, Gestational

Intervention / Treatment
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* Device: Dexcom G6


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-45 years Women with a viable singleton or twin intrauterine pregnancy between 24 0/7 and 31 6/7 weeks gestation based on the best obstetric estimate by ACOG criteria Planning to deliver at OSU Wexner Medical Center Able to understand the study, and having understood, provide written informed consent in English Exclusion Criteria: Abnormal early 50g GCT screen, thereby necessitating 100g OGTT at 24-28 weeks Known pregestational diabetes (type 1, type 2, MODY) 50g GCT >200 mg/dl leading to GDM diagnosis without the performance of 3hr 100g GTT Abnormal obstetrical ultrasound suspicious for major congenital abnormality Known or suspected fetal aneuploidy (by either CVS, amniocentesis, or cell-free DNA) Participation in another trial that may influence the primary outcome, without prior approval Participation in this trial in a prior pregnancy Higher order pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Euglycemic<br>Women who pass a 50g GCT with 1-hour glucose <135 mg/dL | Device: Dexcom G6<br>* Continuous glucose monitoring<br>|
| Possible glucose intolerance<br>Women who fail a 50g GCT (1-hour glucose >135 mg/dL) and have 0/4 abnormal values on a 100g oral glucose tolerance test (OGTT) by Carpenter-Coustan values | Device: Dexcom G6<br>* Continuous glucose monitoring<br>|
| Confirmed glucose intolerance<br>Women who fail a 50g GCT (1-hour glucose >135 mg/dL) and have 1/4 abnormal values on 100g GTT test by Carpenter-Coustan values | Device: Dexcom G6<br>* Continuous glucose monitoring<br>|
| Gestational Diabetes Mellitus<br>Women who fail a 50g GCT (1-hour glucose >135 mg/dL) and have ≥2/4 abnormal values on 100g GTT test by Carpenter-Coustan values (Table 1), meeting criteria for GDM | Device: Dexcom G6<br>* Continuous glucose monitoring<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in glycemic control over late gestation as measured by A1c | Assessed by changes in glycemic control over late gestation as measured by HbA1c at the time of enrollment and delivery | 9 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The number of neonatal hypoglycemic episodes | Assessed by requirement of neonatal antidiabetic care measured in the number of hypoglycemic episode requiring IV dextrose treatment | 1 week |