Hybrid Closed-Loop Therapy Effective for Pregnant Women with Type 1 Diabetes


New results from the AiDAPT trial show hybrid closed-loop therapy significantly improves maternal glycemic control during pregnancy complicated by T1D.

Helen Murphy, MD | Image Credit: Diabetologia

Helen Murphy, MD

Credit: Diabetologia

Hybrid closed-loop insulin therapy significantly improved maternal glycemic control during pregnancy in women with type 1 diabetes (T1D), allowing them to better manage blood glucose compared with traditional methods, according to new research.1

Results from the AiDAPT trial, presented at the 2023 European Association for the Study of Diabetes (EASD) Meeting, suggested the time-in-range benefits were enabled by a reduction in maternal hyperglycemia alongside an increase in nocturnal time in the target range.

“We know that for women with T1D, unborn babies are exquisitely sensitive to small rises in blood sugars, so keeping blood sugar levels within the normal range during pregnancy is crucial to reduce risks for the mother and child,” said Helen Murphy, MD, lead study author and professor at Norwich Medical School, University of East Anglia.2

Research has shown that 1 in 2 babies born to women with T1D suffer complications, the most common being preterm birth, large birth weight, and admission to the neonatal intensive care unit. These complications are most at-risk with maternal antenatal hyperglycemic – the highest risk is observed among those who begin pregnancy with above-target glycated hemoglobin levels.1 Most pregnant persons with diabetes do not have glucose levels within the pregnancy-specific target range of 63 to 140 mg per deciliter (3.5 to 7.8 mmol per liter).

Studies investigating hybrid-closed loop therapy have reported improved glucose control among nonpregnant adults and children. However, little is known about whether the therapy can achieve the rigid glucose targets needed for optimal pregnancy outcomes. Murphy and colleagues tested the effect of hybrid closed-loop therapy initiated before 16 weeks’ gestation on maternal glucose levels in pregnant women with T1D.

In the AiDAPT trial, pregnant women with T1D and a glycated hemoglobin level of ≥6.5% at 9 sites in the United Kingdom were randomly assigned to receive either standard insulin therapy or hybrid-closed loop therapy, with all using continuous glucose monitoring. The study’s primary outcome was the amount of time in the pregnancy-specific target glucose range; key secondary outcomes included the percentage of time spent in hyperglycemia (glucose level >140 mg per deciliter), overnight time in the target range, glycated hemoglobin level, and safety.

From September 2019 - May 2022, a total of 126 participants were enrolled and 124 were randomized, with 61 assigned to the closed-loop group and 63 to the standard-care group. Participants had a mean age of 31 years and a mean baseline glycated hemoglobin level of 7.7±1.2%.

Upon analysis, the mean percentage of time when maternal glucose levels were in the pregnancy-specific target range differed between trial groups. Investigators observed an increase from 47.8±16.4% at baseline to 68.2±10.5% during treatment in the hybrid closed-loop group, and from 44.5±14.4% at baseline to 55.6±12.5% in the standard care group (mean adjusted difference, 10.5 percentage points; 95% CI, 7.0 - 14.0; P <.001). No variations were noted in the treatment effect among trial sites, or across maternal age, glycated hemoglobin, or insulin delivery groups.

Regarding secondary outcomes, the hybrid closed-loop therapy group spent less time in a hyperglycemic state than the standard-care group (mean difference, –10.2 percentage points; 95% CI, –13.8 to –6.6). In addition, the closed-loop therapy group had more overnight time within the target range (mean difference, 12.3 percentage points; 95% CI, 8.3 to 16.2) and lower glycated hemoglobin levels (mean difference, –0.31 percentage points; 95% CI, –0.50 to –0.12).

Safety results showed 6 severe hypoglycemia events in the closed-loop group, compared to 5 in the standard care group, with 1 diabetic ketoacidosis event in each group. The incidence of hypoglycemia was low and did not differ between groups.

In a linked editorial, Satish K. Garg, MD, and Sarit Polsky, MD, MPH, of the Barbara Davis Center for Diabetes, University of Colorado, Denver, noted that the importance of these findings cannot be understated for pregnant persons with T1D. However, they noted major implementation barriers to hybrid closed-loop therapy exist within T1D and continue to contribute to an inability to achieve optimal glucose control.3

“Clearly, closed-loop systems have changed the landscape of diabetes care in nonpregnant populations,” they wrote. “Although more studies are needed, the AiDAPT trial provides hope that this landscape may also be altered for the better for pregnant persons with T1D.”


  1. UK study shows hybrid closed-loop technology improved maternal glucose levels during pregnancy complicated by type 1 diabetes. EurekAlert! October 5, 2023. Accessed October 6, 2023. https://www.eurekalert.org/news-releases/1003774.
  2. Lee TTM, Collett C, Bergford S, et al. Automated Insulin Delivery in Women with Pregnancy Complicated by Type 1 Diabetes [published online ahead of print, 2023 Oct 5]. N Engl J Med. 2023;10.1056/NEJMoa2303911. doi:10.1056/NEJMoa2303911
  3. Garg SK, Polsky S. Technology Use and Glycemic Outcomes during Pregnancy with Type 1 Diabetes [published online ahead of print, 2023 Oct 5]. N Engl J Med. 2023;10.1056/NEJMe2310798. doi:10.1056/NEJMe2310798
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