New Insulin Delivery Technology Improves Glucose Control in Pregnancy: JAMA

An international study co-led by University of Calgary researchers found that advanced insulin-delivery technology significantly improves glucose control in pregnant women with Type 1 diabetes, supporting better health outcomes for both mothers and newborns.

The technology, known as automated insulin delivery (AID), mimics a healthy pancreas. The system automatically adjusts the amount of insulin given by a pump in real-time, based on current and predicted glucose levels.

“For pregnant women with Type 1 diabetes, keeping glucose within a healthy range is very important to the health of the woman and fetus,” says an endocrinologist at Foothills Medical Centre in Calgary and Cumming School of Medicine researcher Dr. Lois Donovan, MD, the study co-principal investigator.

In a multicenter clinical trial, published in JAMA, researchers evaluated the impact of a hybrid closed-loop (HCL) insulin therapy treatment regime with standard insulin injections or an insulin pump that was not automated, along with continuous glucose monitoring.

“Keeping blood glucose in the optimal range for pregnancy is exceptionally challenging when someone has Type 1 diabetes, despite their best efforts and the support of dedicated health care clinics,” says Dr. Denice Feig, MD, the study’s other co-principal investigator. She is an endocrinologist and clinician scientist at the Lunenfeld-Tanenbaum Research Institute, Sinai Health, and a professor of Medicine at the University of Toronto.

Risks in pregnancy

Risks associated with Type 1 diabetes in pregnancy can include increased chances of miscarriage, preeclampsia, which involves dangerous spike in blood pressure, and other significant health concerns. Newborns of pregnant women with Type 1 diabetes are more likely to be born excessively large or early and have low blood glucose at birth and are at higher risk of birth defects.

“The study found this AID system worked in pregnancy. It resulted in a three hours per day improvement in the time spent in the desired glucose range compared to the standard delivery with insulin injections or regular insulin pumps,” says Donovan. “This is very important because we have learned from other larger studies that every 72 minute per day increase, with glucose in the desired range during pregnancy, is associated with reduction in newborn complications.”

The AID system used in the study is knowns as a Tandem t:slim X2 insulin pump with Control-IQ technology.

“We’ve known for a while that AID systems have achieved better glucose control with less diabetes management burden in non-pregnant people with Type 1 diabetes, but its use had not been well studied in pregnancy,” Donovan says. “Most AIDs were not designed to achieve the narrow glucose range desired in pregnancy or to adapt quickly enough to the changing insulin requirement of pregnancy.”

14 sites in Canada and Australia involved

The study found those using the AID spent more time in a healthy glucose level range and less time below and above the healthy range. The improvement in blood sugar control was immediate and persisted throughout the pregnancy. These results were found at all 14 sites involved in the trial.

“This finding will help inform people who are pregnant or planning pregnancy regarding the benefits of this AID system, which can help them achieve better glucose levels in pregnancy and hopefully better pregnancy outcomes” says Feig.

Reference:

Donovan LE, Lemieux P, Dunlop AD, et al. Closed-Loop Insulin Delivery in Type 1 Diabetes in Pregnancy: The CIRCUIT Randomized Clinical Trial. JAMA. Published online October 24, 2025. doi:10.1001/jama.2025.19578.