Wearing a CGM can alleviate some of the burdens associated with managing diabetes, while simultaneously enabling healthcare providers to make more informed and timely treatment decisions. Although the use of CGMs in pregnancy—particularly for gestational diabetes—has been underutilized, there is growing momentum behind its application. 

CGMs have been used with great success in people with type 1 and type 2 diabetes, so why aren’t they more widely used in pregnancy? One reason is that the research on CGM use in pregnancy pales in comparison to the other types of diabetes. A robust body of data is required to inform American College of Obstetrics and Gynecology (ACOG) guidelines, therefore leaving us wanting for solid recommendations. 

Although there aren't set guidelines for CGM use in gestational diabetes, early research shows the benefits of incorporating the technology in prenatal care. In this post, we’ll explore the proven benefits of CGM technology in pregnancy and how you can effectively integrate it into your clinical practice.

Lower Average Blood Glucose and Reduce Maternal Weight Gain

Managing gestational diabetes is all about achieving blood glucose levels that reduce maternal and infant complications. A 2022 meta-analysis by Garcia-Mareno et al found that patients with gestational diabetes (GDM) who used CGM achieved lower average blood glucose levels and lower maternal weight gain and infant birth weight than those using conventional finger-stick blood glucose monitoring (SMBG).¹ 

Similar results were found in a recent trial comparing real-time CGM (rt-CGM) with the use of SMBG for the management of GDM.² CGM users spent significantly more time in range (60-140 mg/dL) than those doing fingersticks.

Likewise, the Flash Glucose Monitoring in Gestational Diabetes Mellitus (FLAMINGO) randomized control trial revealed the positive impact of CGM on glucose levels.³ While mean glucose between the control (SMBG) and intermittently-scanned CGM groups wasn’t significant, the CGM group significantly reduced fasting and postprandial glucose levels during the first 4 weeks following GDM diagnosis.

Lowering the mean glucose levels in pregnancy has multiple benefits for the baby, and simply replacing fingersticks with CGM technology may make it easier to achieve.

Detect High-Risk Patients

Even short-term (14-day) CGM use can help identify patients with a higher risk profile. In a prospective cohort study by Liang et al, CGM-derived data correlated with pregnancy outcomes.⁴ A higher number of values above the target range per sensor data was associated with greater NICU admissions. The research team found that CGM use for 14 days could be used to design interventions for high-risk pregnancies to improve health status among patients with gestational diabetes.

Potential Alternative to Oral Glucose Tolerance Test

Many patients dread the oral glucose tolerance test (OGTT). While it seems simple enough—consume glucose and draw labs—the patient experience is not always ideal. Emerging research is supporting the use of CGM as a viable alternative. Researchers surveyed pregnant patients to evaluate the acceptability of the OGTT vs. CGM to diagnose GDM.⁵ CGM use was preferred by 81% of polled participants, and 93% of participants recommended it for GDM diagnosis. 

One major upside to CGM diagnostic use is that it directly measures the high blood sugars in a real-world scenario, which the OGTT is supposed to predict.

Overall, the research implies that CGM use in gestational diabetes is advantageous.  The technology has the potential to improve monitoring, care, and outcomes while enhancing the patient experience.  However, more conclusive data is needed to change existing guidelines. To that end, multiple research projects are underway to further study the benefits of CGM use in pregnancy.

Current Clinical Trials Involving CGM Use in Gestational Diabetes

The demand for validation of CGM use in GDM is evident. Fortunately, there are many research teams currently studying the technology. Some clinical trials that are underway include:

• A Study on the Use of Real-Time Continuous Glucose Monitoring (RT-CGM) in Gestational Diabetes: The purpose of this study is to examine whether rt-CGM use improves glucose control, maternal outcomes, and fetal outcomes in patients diagnosed with gestational diabetes.
• Glycemic Observation and Metabolic Outcomes in Mothers and Offspring study (GO MOMs): Identifying hyperglycemia early may be optimal for pregnancy outcomes. The goal of this observational cohort study is to use CGM screening in early pregnancy to have a better understanding of hyperglycemia throughout pregnancy and inform future GDM treatment options.
• Effectiveness of CGMS vs. Self-monitoring Blood Glucose (SMBG) in Women With Gestational Diabetes (STEADYSUGAR): This research project is evaluating the use of CGM in early GDM diagnosis, if CGM data can moderate treatment strategies, and whether CGM use can improve outcomes in pregnancy.
• CAPO: Continuous Glucose Monitoring in A2 Gestational Diabetes and Pregnancy Outcomes (CAPO): Honing in on patients with medication-treated GDM, this interventional study team is hypothesizing that the use of CGM in high-risk participants will improve outcomes.
• Time-in-range Using Continuous Glucose Monitoring Management of Gestational Diabetes Mellitus: The aim of this interventional study is to determine if CGM use in GDM patients improves TIR when compared to fingerstick SMBG. 
• Predicting Dysglycemia in Individuals With Gestational Diabetes Immediately Postpartum Using Continuous Glucose Monitoring (PREDISPOSE): The research team of this prospective cohort study is examining the potential of CGM use immediately after delivery to estimate the risk of postpartum hyperglycemia.

Making CGMs Work for Your Obstetrics Practice

Using CGM technology to support pregnancies complicated by diabetes has many potential benefits. There’s the potential to reduce glucose levels and maternal weight gain, lower the risk of macrosomia, and better inform behavior modification. 

While the potential benefits are there, ACOG guidelines for monitoring and treatment continue to be based around fasting and postprandial glucose values.  These guidelines have been built up through decades of research, and changing them will take time and more rigorous research.

That said, there are ways to make CGMs compatible with ACOG guidelines by calculating fasting and postprandial glucose directly from the CGM data.  With a connected app like LilyLink, patients just need to enter their meal and wakeup times and this data can be extracted.  Apps can also make it easy for providers to view patient data through a centralized dashboard.

It’s critical any app for pregnancy sets the proper recommended glucose ranges, which differs from Type 1 and 2. 

Book a demo to see how we can collaborate to deliver cutting-edge, data-driven solutions that will transform the future of prenatal care.

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1. García-Moreno RM, Benítez-Valderrama P, Barquiel B, et al. Efficacy of continuous glucose monitoring on maternal and neonatal outcomes in gestational diabetes mellitus: a systematic review and meta-analysis of randomized clinical trials. Diabet Med. 2022;39(1):e14703. doi:10.1111/dme.14703
2. Valent AM, Huertas-Pagan C, Ward L, Rickert MC, Rincon M. 259-OR: Real-time CGM achieves higher TIR among pregnant persons with GDM. Diabetes. 2024;73(Supplement_1):259–OR. doi:10.2337/db24-259-OR.
3. Majewska A, Stanirowski PJ, Tatur J, et al. Flash glucose monitoring in gestational diabetes mellitus (FLAMINGO): a randomised controlled trial [published correction appears in Acta Diabetol. 2023 Oct;60(10):1439. doi: 10.1007/s00592-023-02159-z]. Acta Diabetol. 2023;60(9):1171-1177. doi:10.1007/s00592-023-02091-2
4. Liang X, Fu Y, Lu S, et al. Continuous glucose monitoring-derived glycemic metrics and adverse pregnancy outcomes among women with gestational diabetes: a prospective cohort study. Lancet Reg Health West Pac. 2023;39:100823. Published 2023 Jun 12. doi:10.1016/j.lanwpc.2023.100823
5. Di Filippo D, Darling J, Chang MHY, Henry A, Welsh A. Oral glucose tolerance test and continuous glucose monitoring for gestational diabetes diagnosis: a survey study of women and health care professionals. Arch Gynecol Obstet. 2024 Feb;309(2):483-489. doi: 10.1007/s00404-023-06949-2.