Postpartum Glycemia in Women at Risk For Persistent Hyperglycemia

Study Overview
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Brief Summary
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GDM is characterized by decreased insulin sensitivity, decreased insulin secretion, or a combination of both. Women with GDM are at significant risk for overt T2DM later in life, and postpartum insulin sensitivity and secretion in women with GDM has not been quantified, limiting our ability to optimize screening for overt T2DM. In addition, compliance with currently recommended postpartum T2DM screening by OGTT is poor. Quantification of postpartum insulin sensitivity and secretion in women at high risk for T2DM will inform strategies to improve diagnostic strategies. Continuous glucose monitoring (CGM) is a new technology that may be useful to identify women with persistent hyperglycemia. Understanding maternal glycemia and physiology that drives glycemia in the postpartum period is limited. Completion of this study will define postpartum maternal glycemia, quantify insulin secretion versus insulin sensitivity defects, and demonstrate the feasiblity of using continuous glucose monitoring to identify women most at risk for overt T2DM.

Official Title
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Postpartum Glycemia in Women at Risk For Persistent Hyperglycemia

Conditions
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Gestational Diabetes

Intervention / Treatment
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* Diagnostic Test: 2-hour 75-g oral glucose tolerance test and Dexcom G6 Pro continuous glucose monitor


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria for early GDM women: Live singleton gestation with no fetal anomalies at 34-40 weeks gestation Gestational diabetes mellitus identified at < 20 weeks' gestation requiring pharmacologic treatment (class A2) Exclusion Criteria for early GDM women: History of prediabetes or polycystic ovarian syndrome History of pregestational type 2 diabetes mellitus Skin conditions which prevent wearing a continuous glucose monitor Inclusion Criteria for 3rd trimester GDM women: Live singleton gestation with no fetal anomalies at 34-40 weeks gestation Gestational diabetes mellitus identified at >= 24 weeks' gestation requiring pharmacologic treatment (class A2) Exclusion Criteria for 3rd trimester GDM women: History of prediabetes or polycystic ovarian syndrome History of pregestational type 2 diabetes mellitus Skin conditions which prevent wearing a continuous glucose monitor

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Postpartum GDM<br>Women with GDM diagnosed early (< 20 weeks gestation) or with routine 3rd trimester screening (>=24 weeks) will be enrolled in this longitudinal study. All enrolled women will complete a oral glucose tolerance test and wear a continuous glucose monitor for 10 days at the 3 designated study time points (0-4 days, 4-6 weeks, and 6 months after delivery). | Diagnostic Test: 2-hour 75-g oral glucose tolerance test and Dexcom G6 Pro continuous glucose monitor<br>* All women enrolled in this study will have a 2-hour 75-g oral glucose tolerance test performed immediately postpartum (within 4 days of delivery), at 4-6 weeks postpartum, and at 6 months postpartum. Enrolled women will also wear a continuous glucose monitor for 10 days at each of these time periods. Both women and their infants will have skin fold thickness measured at each of these 3 study visits to estimate body fat composition. Additionally umbilical cord blood and placental biopsies will be collected at delivery and stored for future research.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pancreatic beta cell function | Insulin secretion will be estimated using the Stomvall index and insulin sensitivity using the Matsuda index. | 4-6 weeks after delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maternal glycemia measured by CGM | % time in range | 10 day wear period starting at 0-4 days, 4-6 weeks, and 6 months after delivery | 
| Maternal hyperglycemia measured by CGM | % time above range | 10 day wear period starting at 0-4 days, 4-6 weeks, and 6 months after delivery | 
| Maternal glucose variability | Coefficient of variation (glucose standard deviation/mean glucose) | 10 day wear period starting at 0-4 days, 4-6 weeks, and 6 months after delivery | 
| Pancreatic beta cell function | Insulin secretion will be estimated using the Stomvall index and insulin sensitivity using the Matsuda index. | 0-4 days and 6 months after delivery | 
| Maternal and infant body fat composition | Percentage body fat calculated from skin fold thickness measurements of upper mid-arm, triceps, subscapular, and flank along with height and weight for the mother and length, birthweight and head circumference for the infant. | 0-4 days, 4-6 weeks, and 6 months after delivery | 
| Maternal diabetes mellitus | Fasting blood glucose >= 126mg/dL or 2-hour blood glucose >=200 mg/dL after 75g oral glucose load. | 4-6 weeks and 6 months after delivery |