New Trial Shows Benefits of Hybrid Closed Loop in Pregnancy  

A JDRF UK-supported trial published in the New England Journal of Medicine and presented at the 2023 European Association for the Study of Diabetes conference demonstrated that hybrid closed loop technology helps pregnant individuals better manage their blood glucose compared to traditional insulin pumps or multiple daily injections.  

Authors say that hybrid closed-loop technology should be offered to all pregnant people with type 1 diabetes.

How does type 1 diabetes (T1D) affect pregnancy?

Despite technological advances in monitoring blood glucose and delivering insulin, altered eating behaviours and hormonal changes during pregnancy mean that most pregnant individuals with T1D struggle to reach the recommended blood glucose levels, which increases complications for both the baby and pregnant individual.

These complications can include premature birth, need for intensive care after birth, and being too large at birth, which increases the lifelong risk of overweight and obesity. Low blood glucose, excess weight gain, and high blood pressure during pregnancy are common amongst pregnant individuals with T1D.

What did the study look at?

In the study, researchers trialed a hybrid closed-loop system also known as the artificial pancreas. They compared this technology with traditional continuous glucose monitoring and insulin systems, where pregnant individuals supported by specialist diabetes maternity teams make multiple daily decisions about insulin doses.

The study involved 124 pregnant individuals with T1D aged 18-45 years who managed their condition with daily insulin therapy. They took part for approximately 24 weeks (from 10-12 weeks gestation until the end of pregnancy). The study took place in nine NHS hospitals in England, Scotland, and Northern Ireland.

What did the study demonstrate?

Using the hybrid closed-loop technology helped to substantially reduce maternal blood glucosethroughout pregnancy.

Compared to traditional insulin therapy methods, the pregnant individuals who used the hybrid closed-loop technology spent more time in the target range for pregnancy blood glucose levels (68% vs 56% of time in range – equivalent to an additional 2.5-3 hours every day throughout pregnancy).

The technology was safely initiated during the first trimester, which is a crucially important time for fetal development. The blood glucose levels improved consistently in the hybrid closed-loop users, regardless of their previous blood glucose levels or previous method of insulin therapy.

These improvements were achieved without additional hypoglycemic episodes and without additional insulin. The participants using the technology also gained 3.5 kg less weight and were less likely to have blood pressure complications during pregnancy.

Importantly, the pregnant participants using the technology also had fewer prenatal clinic appointments, and fewer out-of-hours calls with maternity clinic teams, suggesting that this technology could also be time-saving for pregnant individuals and for stretched maternity services.

The authors of the study say that, as a result of these findings, this type of technology should now be offered to all pregnant individuals with T1D to help improve maternal blood glucose management.

What do the researchers say?

“For a long time, there has been limited progress in improving blood sugars for women with type 1 diabetes, so we’re really excited that our study offers a new option to help pregnant women manage their diabetes,” says lead author, Professor Helen Murphy of the University of East Anglia.

“Previous studies have confirmed that every extra hour spent in the blood sugar target range reduces the risks of premature birth, being too large at birth and need for admission to neonatal intensive care unit. This technology will allow more women to have safer, healthier, more enjoyable pregnancies, with potential for lifelong benefits for their babies.

What does this mean for Canadians with T1D?

There is currently no Canadian recommendation regarding the use of hybrid closed-loop systems during pregnancy. Since 2021, the Diabetes Canada Clinical Practice Guidelines have recommended that “In pregnant people with type 1 diabetes, real-time CGM should be used to increase time-in-range and reduce the risk of overweight infants, neonatal hypoglycemia and intensive care admissions >24 hours.”

In Canada, there are currently two approved options for hybrid closed-loop systems (Medtronic Minimed 770 / 780G or Tandem t:slim X2 + Dexcom G6 with Control-IQ software). JDRF Canada regularly monitors Health Canada approvals for diabetes technology and will continue to review further studies on diabetes technology in pregnancy, and provide updates based on their results.

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