Continuous Glucose Monitoring for Women with Gestational Diabetes, CORDELIA: A Multicentric Randomized Controlled Trial, Methodology and Design

Background/Objectives: Gestational diabetes mellitus (GDM) is associated with increased short- and long-term risks for both mother and child. Screening and treatment between 24 and 30 weeks’ gestation reduces adverse pregnancy outcomes, while emerging evidence suggests that earlier diagnosis and treatment (<20 weeks’) in high-risk populations may further improve neonatal outcomes. Currently, self-monitoring of blood glucose (SMBG) remains the standard of care for management but provides only intermittent glycemic data and limited insight into overall glucose patterns. Real-time continuous glucose monitoring (rt-CGM) has transformed management in pregnancies complicated by type 1 diabetes but has shown conflicting results in GDM; it is thus unclear whether similar benefits may extend to women with GDM, including women with early GDM. Methods: The Continuous Glucose Monitoring for Women With Gestational Diabetes (CORDELIA) study is an ongoing, large, open-label, multicenter randomized controlled trial conducted across 14 centers in Belgium and two centers in Australia. Women diagnosed with GDM are randomized in a 1:1 ratio to either rt-CGM (intervention group) or standard care with SMBG (control group). Both women with early GDM diagnosed before 20 weeks’ gestation and those diagnosed between 24.0 and 29.6 weeks’ gestation are included. Participants attend the following visits: baseline visit at GDM diagnosis, an additional visit at 20.0–23.9 weeks’ (if early GDM), 31.0–33.6 weeks’ and 36.0–38.6 weeks’, and a postpartum oral glucose tolerance test (OGTT) assessment (6.0–23.6 weeks after delivery). At each visit, clinical assessment, HbA1c, and (blinded) CGM are evaluated, alongside validated patient-reported outcome questionnaires. The primary objective is to compare the incidence of a composite of adverse pregnancy outcomes between the rt-CGM and SMBG groups. The primary outcome is a composite of adverse pregnancy outcomes including preterm delivery <37 weeks, LGA [customized percentiles according to Gestation Related Optimal Weight chart (GROW)], neonatal hypoglycemia requiring intravenous dextrose, neonatal intensive care unit (NICU) admission > 24 h, neonatal respiratory distress, stillbirth or neonatal death, phototherapy, birth trauma, and shoulder dystocia. Secondary outcomes include maternal glycemia, insulin use, pregnancy and neonatal outcomes, glycemic variability, patient-reported outcomes, and prespecified secondary analyses according to timing of GDM diagnosis and maternal BMI. Trial Registration: ClinicalTrials.gov: NCT06310356. First posted: 15 March 2024.