Pregnant Women Managing Diabetes with Dexcom G6 CGM System

Continuous glucose monitoring systems like the Dexcom G6 can enable pregnant women to monitor blood glucose more effectively. 

Pregnant women with diabetes have a higher risk of adverse pregnancy outcomes. Stricter glucose goals are suggested to manage glucose levels but can increase the risk of hypoglycemia, so constant glucose monitoring for pregnant women is essential for improved glycemic control. In a previous study, continuous glucose monitoring (CGM) was shown to improve pregnancy outcomes. Prior studies have demonstrated the advantages of continuous glucose monitoring over self-monitoring of blood glucose. Even though CGM systems are beneficial during pregnancy, most current CGM systems still do not include indications for pregnancy use. 

The study aims to examine the Dexcom G6 CGM System’s effectiveness in 18- to 41-year-old pregnant women with diabetes. Pregnant women included in the study were in the second or third trimester, with 19 (60%) participants in the second trimester. The study included 32 participants evaluated at three sites in the study. There were participants with type 1, type 2, and gestational diabetes included in the study, with 20 (62.5%) participants with type 1 diabetes. CGM was previously used in 18 (56%) of the participants in the past six months. Participants in the study received two CGM devices that were either worn on the back of the upper arm, the abdomen, or upper buttocks for ten days. Participants with skin conditions that interfere with the sensors and conditions that increased adverse outcomes were excluded from the study. The participants went through a 6-hour clinic session between the 3rd and 7th day of wearing the sensor. Accuracy was determined in this study by the Dexcom G6 CGM system values being within 20% of the YSI reference values. 

In this study, 36.8% of sensors were placed on the abdomen, 38.2% of sensors were placed on the arm, and 25% of sensors were placed on the buttock. The most common configuration was 16 (50%) of participants inserting the sensors on the abdomen and upper arm. When comparing values to the YSI reference, the Dexcom G6 CGM system was 92.5% accurate. Sensors inserted on the abdomen were 91.6% accurate, with sensors inserted on the buttock being 87.7% accurate. The posterior upper arm was the most accurate of the sensor sites, with 95.9% accuracy. The mean absolute relative difference (MARD) was found to be 10.3%. For the sensors placed on the abdomen, the mean absolute relative difference was 11.5%. The MARD for the sensor placed on the buttock was 11.2%, and the sensors on the back of the arm were 8.7%. There were no adverse effects related to the Dexcom G6 System. Eight participants had minimal skin reactions at the insertions site. 

A previous study in Diabetes Technology & Therapeutics showed that the Dexcom G6 system inserted on non-pregnant adults’ abdomens was 92.5% accurate. This study showed that the Dexcom G6 system performs similarly in pregnant and non-pregnant adults. 

The use of the Dexcom G6 CGM System is beneficial in pregnant women with diabetes. The results showed that the sensor on the back of the upper arm provided the most accurate readings, and the participants tolerated the Dexcom G6 system well.  

This study furthers the use of a continuous glucose monitoring system in pregnant women. Continuous glucose monitoring systems can provide pregnant women with a more straightforward way to monitor blood glucose.   

A limitation of the study was the small number of participants. CGM system accuracy in managing diabetes is essential for pregnant women because of the stricter glucose goals. Further studies should assess the Dexcom G6 features that are beneficial during pregnancy to improve glucose management. 

Practice Pearls: 

• The Dexcom G6 system was 92.5% accurate compared to the reference value.  
• Continuous glucose monitoring system accuracy is essential due to the stricter glucose ranges during pregnancy. 
• Continuous glucose monitoring is associated with improved pregnancy outcomes.  

Castorino, Kristin, et al. “Performance of the Dexcom G6 Continuous Glucose Monitoring System in Pregnant Women with Diabetes.” Diabetes Technology & Therapeutics, vol. 22, no. 12, Dec. 2020, pp. 943–47, doi:10.1089/dia.2020.0085.  

Shah, Viral N et al. “Performance of a Factory-Calibrated Real-Time Continuous Glucose Monitoring System Utilizing an Automated Sensor Applicator.“ Diabetes technology & therapeutics, vol. 20,6 (2018): 428-433. doi:10.1089/dia.2018.0143 

Alexis Dunn, PharmD. Candidate, Florida Agricultural & Mechanical University, College of Pharmacy and Pharmaceutical Sciences