The Expanding Role of Continuous Glucose Monitors in Pregnant Patients
The use of CGMs in pregnancy provides clinicians with essential data in real-time, rather than a snapshot given by traditional finger stick testing.
Patients with diabetes face extra challenges when pregnant because glycemic control is essential for a healthy pregnancy and reducing risks of fetal malformations. Diabetes during pregnancy significantly increases the risk of preeclampsia and elevated maternal risks also include spontaneous abortion and infection.1
The importance of glucose monitoring for this population cannot be overemphasized. The use of continuous glucose monitors (CGMs) for diabetes management in pregnancy provides clinicians with essential data in real-time, rather than a snapshot given by traditional finger stick testing.1
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Multiple CGMs are available on the market today, although most are available by prescription only. Many practitioners are realizing their significant benefits, and third-party payers are expanding their coverage of CGMs.1
All CGMs have 3 essential components for functionality: a sensor, a transmitter, and a receiver. Patients can often use a compatible smartphone with the appropriate application installed in place of the receiver.1
Available brands include Dexcom, Freestyle Libre, Medtronic, and Eversense. With the exception of Eversense, manufacturers have professional use systems available for clinicians (e.g., Dexcom G6 for patients and Dexcom G6 Pro for professionals) to keep in the office. Providers often give them to patients to wear for a short period of time (10 to 14 days) with the understanding that the patient will return to the office for a review of the data along with the provider. Some CGMs allow advanced integration with insulin pumps.1
A review published in Obstetrics & Gynecology discusses the advantages of CGMs over self-monitoring of capillary blood glucose in pregnant patients. The review presents data from the CONCEPTT trial, which was a multi-center, open-label, randomized control trial of 215 pregnant patients with type 1 diabetes. At this time, the use of CGMs in pregnant patients with type 2 diabetes or gestational diabetes has not been evaluated in a clinical trial, although these trials are upcoming.2
In CONCEPTT, CGM use, in addition to self-monitoring of blood glucose, was associated with reduced maternal hemoglobin A1C and reduced instances of maternal hyperglycemia. The benefits of CGM for the neonate included fewer neonatal intensive care unit admissions, fewer incidences of neonatal hypoglycemia, and lower incidence of large-for-gestational age neonates.2
Patients can access a multitude of metrics through CGMs. One such metric is time spent in target glucose ranges. The target range for pregnant patients (63 mg/dL to 140 mg/dL) is lower than that of the general population.2
The CONCEPTT researchers recommended that pregnant patients be in the target range 70% of the time, above range less than 25% of the time, and below range less than 4% of the time. CGMs can alert patients when their readings are outside of target range. These alerts and readings can impact medication choices and insulin dose adjustments.2
Additionally, CGMs can provide information not gained through traditional point of care testing, hemoglobin A1C tests, or oral glucose tolerance tests. CGMs show the impact of diet and lifestyle modifications.
CGMs have shown effectiveness in maternal and neonatal outcomes in pregnant patients with type 1 diabetes. As clinicians realize the benefit to all pregnant patients with diabetes, use of CGMs will become standard practice.
