CGM Accuracy in Pregnancy Study

Hospital Mutua de Terrassa

Status: Not yet enrolling

Conditions: Pregestational Diabetes; Continuous Glucose Monitoring

Treatments: Device: Dexcom One Plus; Device: FreeStyle Libre 2 Plus; Procedure: Additional Study Procedures

Study type: Interventional

Funder types: Other

Identifiers

NCT07269015

P/25-041

Details and patient eligibility

About

Pregnancy in women with diabetes remains a high-risk condition, requiring strict glycemic control due to rapid physiological changes that affect insulin sensitivity. Continuous glucose monitoring (CGM) provides detailed glucose trends, but the accuracy of newer, affordable systems such as Dexcom One Plus and FreeStyle Libre 2 Plus has not been evaluated during pregnancy.

This prospective interventional study aims to compare the accuracy of these two CGM systems-both worn simultaneously-using capillary glucose as the reference. The study also evaluates educational needs, skills, attitudes, digital competence, lifestyle habits, and patient-reported outcomes among pregnant women with type 1 diabetes (T1D), type 2 diabetes (T2D), and gestational diabetes (GDM).

Full description

Women with diabetes during pregnancy experience increased risks of congenital malformations, neonatal morbidity, hypertensive disorders, and abnormal fetal growth. Continuous glucose monitoring (CGM) improves glycemic outcomes in type 1 diabetes (T1D) in pregnancy, yet evidence remains limited for type 2 diabetes (T2D) and gestational diabetes (GDM). Dexcom One Plus and FreeStyle Libre 2 Plus are recent low-cost systems with CE-mark approval for use in pregnancy, both with reported Mean Absolute Relative Difference (MARD) values around 8%. However, neither system has been specifically validated in pregnant populations.

Physiological changes in pregnancy-including increased total body water and interstitial fluid-may alter CGM accuracy. Prior studies show that earlier FreeStyle Libre versions may overestimate hypoglycemia in pregnant women. Furthermore, women with T2D or GDM typically have little prior exposure to diabetes education or CGM technology, which may contribute to suboptimal glycemic control.

This study evaluates the accuracy and usability of Dexcom One Plus and FreeStyle Libre 2 Plus during pregnancy, while also assessing educational and digital literacy needs to optimize CGM implementation in real-world clinical practice.

Enrollment: 66 estimated patients

Sex: Female

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Pregnant women with type 1 diabetes, type 2 diabetes, or gestational diabetes, diagnosed before 32 weeks of gestation
• Age ≥18 years
• Willingness to wear two CGM systems simultaneously
• Possession of a smartphone compatible with LibreLink
• Ability to sign informed consent

Exclusion criteria

• Comorbidities affecting glucose metabolism
• Inability to use CGM devices or perform capillary glucose testing

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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66 participants in 1 patient group

Dual Continuous Glucose Monitoring Use

Experimental group

Description:

All participants will wear two continuous glucose monitoring sensors simultaneously

Treatment:

Procedure: Additional Study Procedures

Device: FreeStyle Libre 2 Plus

Device: Dexcom One Plus