Hybrid Closed Loop Insulin Improves Time in Range for T1D During Pregnancy, with Lois Donovan, MD, and Denice Feig, MD, MSc

An automated insulin delivery (AID) system using Control-IQ Technology demonstrated an improved time in blood glucose pregnancy range (TIRp) from standard care in women with type 1 diabetes (T1D) in early pregnancy.1,2

These findings, from the open-label CIRCUIT trial, were presented by co-primary investigator Lois Donovan, MD, endocrinologist and Clinical Professor, Cumming School of Medicine, and Child Health & Wellness Researcher, Alberta Children's Hospital Research Institute, at University of Calgary at the 2025 American Diabetes Association (ADA) Scientific Sessions, held June 20-23, in Chicago, Illinois.

HCPLive caught up with Donovan as well as the study’s other co-primary investigator, Denice Feig, MD, MSc, Professor of Medicine, University of Toronto, and Head of the Diabetes and Endocrine in Pregnancy Program at Mount Sinai Hospital, to learn more about CIRCUIT and its promising findings.

Feig also serves as an Adjunct Scientist at the Institute for Clinical and Evaluative Sciences, is a Member of the Motherisk Team at SickKids Hospital, and was Past Chair of the Diabetes in Pregnancy Interest Group for the ADA.

Donovan and Feig gave an overview of the Control-IQ technology used in the study, which was combined with an insulin pump and a Dexcom G6 sensor. They shared their excitement over the preliminary findings, which included a 12.6% (95% CI, 9.9-15.2; P <.001) higher TIRp with HCL than standard care (65.4%; standard deviation [SD], 9.5% versus 50.3%; SD, 13.9, respectively). HCL was also associated with 11.4% (95% CI, 8.6–14.2; P <.001) less time above range and 1.04% (95% CI, 0.6–1.48; P <.001) less time below 63 mg/dL, along with an adjusted mean glucose 11.2 mg/dL (0.62 mmol/L) lower than standard care (95% CI, 7.2–16.2; P <.001).1

"We're really excited to share with you that we found a 12.6% point improvement in the closed loop group compared to the standard care group... that equates to 3 more hours per day spent in pregnancy time in range, which, as Denice has already beautifully pointed out in previous work, will be very impactful on the pregnancy outcomes. Certainly, this study was not powered to look at pregnancy outcomes, but we're really very excited by how well it worked," Donovan said.

Donovan’s disclosures include Medtronic, Dexcom, Inc., Tandem Diabetes Care, Inc, and Inner Analytics. Feig’s disclosures include Ypsomed and Novo Nordisk

REFERENCES

1. Donovan LE, Lemieux P, Dunlop A, et al. A Randomized Multicenter Trial of Hybrid Closed-Loop Insulin Therapy with Control-IQ Technology in Type 1 Diabetes in Pregnancy. Presented at ADA 2025; June 20-23; Chicago, Illinois. Poster #2084-LB

2. Smart Insulin Tech Helps Pregnant Women with Type 1 Diabetes Maintain Target Blood Glucose Levels. News release. ADA. June 20, 2025. https://www.prnewswire.com/news-releases/smart-insulin-tech-helps-pregnant-women-with-type-1-diabetes-maintain-target-blood-glucose-levels-302487332.html