Patterns and Glycaemic Endpoints for Diagnosing Gestational Diabetes

NCT05981547 | Active Not Recruiting

• 1 other identifier: 325114
• Study Type: observational
• Target: 400
• Locations: 1 country
• Sites: 1

Brief Summary

Gestational diabetes (GDM) develops during pregnancy and is becoming increasingly common. The condition is associated with adverse outcomes for mother and baby during both the pregnancy and delivery period. This study compares glucose variability (recorded by a continuous glucose monitoring (CGM) sensor) in pregnant women who have been diagnosed with GDM with pregnant woman who do not have the diagnosis but are at high risk. The sensors will be applied to 400 participants around the time of their standard test for GDM, with a randomly selected 60 of these patients forming a sub-group later in the study to assess for progression of high blood glucose. At present, a positive oral glucose tolerance test (OGTT) is used to confirm the diagnosis of GDM but the test can be unreliable leading to potential diagnostic error. CGM devices are used extensively in the management of Type 1 diabetes and GDM, and have also shown potential to be used in the diagnosis of Type 2 diabetes. If this study can demonstrate similar trends in glucose variability between OGTT positive patients and those who are OGTT negative but are at high risk for the condition, then further research into the utility of CGM as a diagnostic alternative or supplement to the OGTT would be indicated. The investigators will recruit 400 patients at high risk for GDM, give them a blinded CGM device, and compare the CGM glucose data with their OGTT result, their initial risk factors for GDM, their pregnancy outcome and their need for treatment. The investigators will use the data to test our hypothesis that a positive OGTT result does not predict hyperglycaemia in pregnancy.

Conditions

Gestational Diabetes

Keywords

GDM - gestational diabetes; CGM - continuous glucose monitoring; AGP - ambulatory glucose profile; OGTT - Oral glucose tolerance test; NICE - national institute for health and care excellence; JDANC - Joint diabetes antenatal clinic

Outcome Measures

Primary Outcomes (4)

• Time in range on CGM data (glucose 3.9-10)

  Assessed glucose parameters and trends on ambulatory glucose profile provided by continuous glucose monitoring data.

  12 months

• Time in hyperglycaemia (glucose >10)

  Assessed glucose parameters and trends on ambulatory glucose profile provided by continuous glucose monitoring data.

  12 months

• Glucose management indicator (GMI) - 'estimated A1c'

  CGM device 'estimated A1c' calculation from the available data. This correlates with average glucose level

  12 months

• Glucose variability

  Measure provided by CGM device referring to the amplitude and frequency of variation from the average glucose level. This does not directly correlate with average glucose level.

  12 months

Secondary Outcomes (2)

• Glucose lowering therapy.

  12 months

• A analysis of CGM glucose data for progression of glycaemia in a sub group

  12 months

Interventions

Libre 3 continuous glucose monitoring sensor DEVICE

Libre 3 CGM sensor applied to women prior to their Oral Glucose Tolerance test.

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Needs to be female aged 18 or above, between 12-26 weeks gestation.
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

The investigators will recruit 400 patients, with the expectation that approximately 120 of these will have confirmed GDM following an OGTT. Of these patients, we expect 50% will require glucose lowering therapy (metformin and/or insulin) and 50% willo manage their GDM with dietary measures. The sample sizes are derived from the fact that CGM (AGP) comparisons across groups require n=18-20 in each group to give 80% power to detect clinically significant differences and so our sample size calculations are driven by making sure no sub-group has less than 20 subjects in it. The total of 120 positive OGTTs can be further sub-divided by how they achieved the positive OGTT (fasting, post glucose load, or both).

You may qualify if:

• Female aged 18 years of above
• Between 12-26 weeks gestation
• Identified by NICE as having one or more independent risk factor for GDM
• Suitable for the standard care pathway under the joint antenatal clinic for GDM
• Willing and able to give informed consent.

You may not qualify if:

• Pre-existing diabetes
• Previous GDM
• Unsuitable for standard joint antenatal clinic pathway
• Known allergy to freestyle libre adhesive pad
• Planning to move geographical area during the study timeframe
• Participating in a different study that could interfere with glucose levels or affect ability to participate.

Sponsors & Collaborators

• Portsmouth Hospitals NHS Trust: lead
• Abbott: collaborator

Study Sites (1)

Portsmouth Hospitals University NHS Trust

Portsmouth, United Kingdom

Location

MeSH Terms

Conditions

Diabetes, Gestational

Condition Hierarchy (Ancestors)

Pregnancy Complications; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases

Study Officials

• Laura Marshall, Bsc

  Portsmouth Hospitals University NHS Trust

  STUDY CHAIR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER GOV
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 17, 2023
• First Posted: August 8, 2023
• Study Start: November 22, 2023
• Primary Completion (Estimated): June 21, 2026
• Study Completion (Estimated): June 21, 2026
• Last Updated: December 23, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)