The Need for Automated Insulin Delivery Systems During Pregnancy in Women with Type 1 Diabetes
By Susannah Chen
Researchers at the 2023 ATTD conference discussed the challenge of keeping up with insulin requirements in women with type 1 diabetes during pregnancy. After reviewing current studies involving automated insulin delivery systems in pregnancy, they emphasized the need to include specific software in hybrid closed loop systems for pregnant women with type 1 diabetes.
Using hybrid closed-loop systems in pregnancy would be beneficial for women with type 1 diabetes because they could optimize blood sugar control and improve quality of life, according to researchers who have led relevant studies.
During scientific sessions at the Advanced Technologies and Treatments for Diabetes (ATTD) conference in Berlin, researchers presented data from current and recent studies involving hybrid closed-loop (HCL) systems used during pregnancy that demonstrate pregnancy-specific hybrid closed-loop calculations can help women with type 1 diabetes optimize glycemic control in gestation, improve patient quality of life, and potentially reduce the overall cost of maternal health on the hospital system, emphasizing the need to develop algorithms that are safe and approved for pregnancy.
Currently, one hybrid closed-loop therapy, the CamAPS Fx, has been licensed for use during pregnancy, but it is only approved for use in the United Kingdom and the European Union. In the United States, every available automated insulin delivery (AID) system currently excludes use during pregnancy.
“Could automated insulin delivery help in pregnancy? Yes, by all means,” said Dr. Sarit Polsky, assistant professor and director of the Pregnancy and Women's Health Clinic at the University of Colorado Barbara Davis Center for Diabetes. She cited a handful of current studies PICLS, AiDAPT, CRISTAL, and CIRCUIT, among others—that used HCL devices in pregnancy.
University of Calgary Clinical Professor Lois Donovan discussed the psychological impact of living with type 1 diabetes through pregnancy.
As principal investigator for CIRCUIT, a trial that studies the use of Tandem’s Control-IQ software in pregnant women with type 1, Donovan said that patients reported concerns such as fear of the baby dying, the pressure to care for a human being other than oneself, and the increased burden of work for type 1 women in pregnancy when compared to other pregnant women.
Dr. Helen Murphy, honorary consultant physician at the Cambridge University NHS Foundation Trust, who helped pioneer the micromanagement of diabetes in pregnancy through a series of studies of pregnancy-specific algorithms in hybrid closed-loop therapy now known as the CLIPS studies, discussed the challenges in using AID systems for pregnant women with type 1 diabetes.
Among the challenges she listed for pregnant women with type 1 diabetes: better managing high-carbohydrate meals, developing an AID system that can deliver insulin quickly enough to avoid post-meal high blood sugars, and the challenges of knowing when to increase insulin delivery (such as illness and rising insulin resistance during the third trimester of pregnancy) versus knowing when to reduce or stop insulin delivery (such as following low blood sugar events, hot weather, or physical activity).
One of Murphy’s current studies, AiDAPT—the largest randomized controlled trial to evaluate the impact of closed-loop insulin delivery during type 1 diabetes pregnancy— concludes in 2024 and will evaluate whether automated insulin delivery improves the amount of time pregnant women with type 1 spend in a target glucose range.
Based on the results of her PICLS study, Polsky offered the opinion that clinicians should only medically allow off-label hybrid closed-loop use in individuals who are able to navigate the system using “assisted” techniques to help optimize blood sugars during pregnancy.
Among Polsky’s “assisted” techniques: Using the lowest glucose target level that the system allows, entering “fake carbohydrate boluses'' based on insulin sensitivity, limiting correction boluses to less than once every two hours, pre-bolusing 15 minutes before meals during the first trimester and 45 minutes before meals in the third trimester, and “Super Bolusing,” which refers to when basal insulin delivery is curtailed and delivered as an additional carb or correction bolus instead to create more impact in situations when insulin is needed quickly.
The bottom line: hybrid closed-loop systems can improve glucose control in pregnant women, but they still need plenty of guidance from knowledgeable healthcare providers. As Donovan described the use of automated insulin delivery during pregnancy: “It’s still work. It isn’t just plug-and-play. You have to give [pregnant women with diabetes] support.”