Skip to main content
OpenTrials
Not Yet Recruiting

NCT Number: NCT07269015

CGM Accuracy in Pregnancy Study

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).

Not Yet Recruiting

Trial opening soon.

Get Notified

Key information

Conditions

Pregestational Diabetes Continuous Glucose Monitoring Diabetes Mellitus Diabetes Mellitus, Type 2 Endocrine System Diseases Glucose Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year and older

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Hospital Universitari Mutua Terrassa

Terrassa, Barcelona, 08221, Spain

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Dexcom One Plus

Device

Worn on the upper arm for 10 days Two replacements during the 30-day study period Used with Dexcom mobile application

FreeStyle Libre 2 Plus

Device

Worn on the opposite arm for 15 days One replacement during the 30-day study period Used as real-time CGM via LibreLink

Additional Study Procedures

Procedure

Capillary glucose monitoring before meals, 1 hour postprandially, and during symptoms of hypoglycemia (Contour Instant) One baseline structured education session for participants without prior CGM experience Routine diabetes education according to national guidelines

Primary outcomes

  1. Mean Absolute Relative Difference (MARD)

    Time frame: End of 30-day monitoring period; Primary outcome

    Difference between paired continuous glucose monitoring (CGM) readings (Dexcom One Plus vs. FreeStyle Libre 2 Plus) and reference capillary glucose values.

  2. Baseline diabetes knowledge, skills, and attitudes

    Time frame: Baseline (first study visit)

    For the baseline evaluation, a specific questionnaire for the present study was administered, and the Spanish version of the Cambados Questionnaire will also be used. The Cambados Questionnaire is a 5-item questionnaire designed to assess digital competence. The score range is from 0 to 20. Higher scores indicate greater digital competence.

Secondary outcomes

  1. Mean Absolute Difference (MAD) for glucose <70 mg/dL

    Time frame: End of 30-day monitoring period

    |Difference| between paired values.

  2. Agreement rates (15/15%, 20/20%, 40/40%) across glucose ranges

    Time frame: End of 30-day monitoring period

    Categories: <63, 63-140, <70, 70-180, >140, >180 mg/dL.

  3. Dietary habits (Mediterranean diet adherence)

    Time frame: Baseline and End of 30-day monitoring period

    The Mediterranean Diet Adherence Screener (MEDAS) will be used to evaluate adherence to the Mediterranean diet using a 17-item dietary assessment (score range: 0-17). Higher scores indicate greater adherence to the Mediterranean diet.

  4. Physical activity

    Time frame: 7 days before baseline and through study completion, an average of 1 week

    Physical activity will be assessed by steps per day (measured as total steps) and using the reduced version of the Pregnancy Physical Activity Questionnaire (PPAQ). The reported time spent in each activity category will be multiplied by the established categorical intensity value (METs) associated with that question. The total weekly physical activity level (MET-minutes/week or MET-hours/week) will be calculated by summing the MET values for each item, allowing for classification by intensity (sedentary, light, moderate, and vigorous)

  5. Sleep quality

    Time frame: Baseline and through study completion, an average of 1 week

    Pittsburgh Sleep Quality Index (PSQI). The PSQI is a 19-item, self-rated questionnaire designed to measure sleep quality and disturbance. Sleep component scores will be summed to yield a total score ranging from 0 to 21 with the higher total score (referred to as global score) indicating worse sleep quality

  6. Patient-reported outcomes (PROMs)

    Time frame: Through study completion, an average of 1 week

    The Glucose Monitoring System Satisfaction Survey (GMSS) will be used to assess patients' satisfaction with their continuous glucose monitoring (CGM) system. GMSS is a 15-item questionnaire with a score range of 1 to 5. Higher scores indicate greater satisfaction.

Study contacts

Contact information is provided by the study sponsor or research team.

Verónica Perea, MD, PhD

CONTACT

[email protected]

0043937 36 50 50 ext. 11330

Sponsors and collaborators

Lead sponsor

Hospital Mutua de Terrassa

Other

Registry information

Official study title

Evaluation of the Accuracy of Continuous Glucose Monitoring Systems and Educational Needs in Pregnant Women With Diabetes: A Comparison Between Dexcom One Plus and FreeStyle Libre 2 Plus

Important dates

Study start
2025
Primary completion
2026
Study completion
2027
First posted
Dec 8, 2025
Registry last updated
Dec 8, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.