Closed-loop Insulin Delivery In Type 1 Diabetes Pregnancies (CIRCUIT)

NCT04902378 | Completed DMC

• 1 other identifier: REB20-1266
• Study Type: interventional
• Target: 94
• Locations: 2 countries
• Sites: 14

Brief Summary

This trial will assess the efficacy of the Tandem t:slim X2 insulin pump with Control IQ technology compared with standard insulin delivery plus CGM in pregnant women with type 1 diabetes.

Conditions

Type 1 Diabetes Mellitus; Pregnancy Related; Glucose Metabolism Disorders; Metabolic Disease; Endocrine System Diseases

Keywords

Type 1 diabetes, pregnancy, closed-loop, clinical trial

Outcome Measures

Primary Outcomes (1)

• Glycemic control as reflected by percent glucose time-in-range

  Time in range (3.5 to 7.8 mmol/L) per day assessed by CGM glucose measurement

  16 weeks until 34 weeks gestation

Secondary Outcomes (27)

• Percent time spent above target range per day (+/-SD)

  16 weeks gestation until delivery of neonate

• Percent time spent below target range per day (+/-SD)

  16 weeks gestation until delivery of neonate

• Mean blood glucose measurement at 24 and 34 weeks (+/-SD)

  24 and 34 weeks gestation

• Proportion of participants who experience maternal hypoglycemic events

  16 weeks gestation until delivery of neonate

• Glycemic variability reflected by the coefficients of variation and standard deviations of CGM data

  16 weeks gestation until delivery of neonate

Study Arms (2)

Tandem t:slim X2 insulin pump with Control IQ technology plus CGM

EXPERIMENTAL

Participants randomized to the intervention group will be fitted with the Tandem t:slim X2 insulin pump with Control IQ technology and Dexcom G6 Continuous Glucose Monitor.

Device: Tandem t:slim X2 insulin pump with Control IQ technology

Standard insulin delivery (multiple daily injections (MDI) or pump) and CGM

NO INTERVENTION

Participants randomized to the control group will be fitted with the Dexcom G6 Continuous Glucose Monitor. They will continue to use standard insulin delivery (MDI or pump) and CGM.

Interventions

Tandem t:slim X2 insulin pump with Control IQ technology DEVICE

The intervention group will be fitted with the Tandem t:slim X2 insulin pump with Control IQ technology during pregnancy.

Tandem t:slim X2 insulin pump with Control IQ technology plus CGM

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Between 18 and 45 years of age (inclusive)
• A diagnosis of type 1 diabetes, as defined by Diabetes Canada, for at least 12 months
• A viable singleton pregnancy confirmed by ultrasound, less than 14 weeks gestation
• Currently on intensive insulin therapy (≥ 3 injections, or Continuous subcutaneous insulin infusion (CSII)
• Willingness to use the study devices throughout the trial
• A1c ≥ 6.2% and \<10% measured any time during pregnancy prior to enrollment
• Able to provide informed consent
• Have access to email

You may not qualify if:

• Non-type 1 diabetes
• Current treatment with drugs known to interfere with glucose metabolism as judged by the investigator such as high dose systemic corticosteroids
• Known or suspected allergy to insulin
• Women with nephropathy (estimated glomerular filtration rate \[eGFR\] \<45), severe autonomic neuropathy, uncontrolled gastroparesis or severe proliferative retinopathy, as judged by the investigator, that is likely to interfere with the normal conduct of the study and interpretation of study results
• Total daily insulin dose \<8 or \>250 units/day at screening
• Severe visual or hearing impairment, as judged by the investigator to impact treatment compliance
• Unable to communicate effectively in English or French as judged by the investigator
• Current use of Tandem Control IQ, DIY looping system, 670G in Auto Mode, or alternate closed-loop system as judged by the investigator
• Any reason judged by the investigator that would likely interfere with the normal conduct of the study and interpretation of study results

Sponsors & Collaborators

• University of Calgary: lead

Study Sites (14)

Campbelltown Hospital

Campbelltown, 2560, Australia

Location

Royal Prince Alfred Hospital

Camperdown, Australia

Location

Canberra Hospital

Garran, Australia

Location

Royal Women's Hospital

Parkville, Australia

Location

Westmead Hospital

Westmead, Australia

Location

University of Calgary

Calgary, Alberta, T2T 5C7, Canada

Location

BC Women's Hospital

Vancouver, British Columbia, Canada

Location

University of Manitoba

Winnipeg, Manitoba, R3E 3P4, Canada

Location

IWK Health Centre

Halifax, Nova Scotia, B3K 6R8, Canada

Location

Lawson Health Research Institute

London, Ontario, N6C 2R5, Canada

Location

Sunnybrook

Toronto, Ontario, M4N 3M5, Canada

Location

Mount Sinai Hospital

Toronto, Ontario, M5T 3L9, Canada

Location

University of Montreal - CHUM

Montreal, Quebec, H2X 3J4, Canada

Location

Université Laval

Québec, Quebec, G1V 4G2, Canada

Location

Related Publications (15)

• Persson M, Norman M, Hanson U. Obstetric and perinatal outcomes in type 1 diabetic pregnancies: A large, population-based study. Diabetes Care. 2009 Nov;32(11):2005-9. doi: 10.2337/dc09-0656. Epub 2009 Aug 12.

  PMID: 19675195 BACKGROUND

• Feig DS, Hwee J, Shah BR, Booth GL, Bierman AS, Lipscombe LL. Trends in incidence of diabetes in pregnancy and serious perinatal outcomes: a large, population-based study in Ontario, Canada, 1996-2010. Diabetes Care. 2014 Jun;37(6):1590-6. doi: 10.2337/dc13-2717. Epub 2014 Apr 4.

  PMID: 24705609 BACKGROUND

• Evers IM, de Valk HW, Visser GH. Risk of complications of pregnancy in women with type 1 diabetes: nationwide prospective study in the Netherlands. BMJ. 2004 Apr 17;328(7445):915. doi: 10.1136/bmj.38043.583160.EE. Epub 2004 Apr 5.

  PMID: 15066886 BACKGROUND

• Murphy HR, Roland JM, Skinner TC, Simmons D, Gurnell E, Morrish NJ, Soo SC, Kelly S, Lim B, Randall J, Thompsett S, Temple RC. Effectiveness of a regional prepregnancy care program in women with type 1 and type 2 diabetes: benefits beyond glycemic control. Diabetes Care. 2010 Dec;33(12):2514-20. doi: 10.2337/dc10-1113.

  PMID: 21115765 BACKGROUND

• Maresh MJ, Holmes VA, Patterson CC, Young IS, Pearson DW, Walker JD, McCance DR; Diabetes and Pre-eclampsia Intervention Trial Study Group. Glycemic targets in the second and third trimester of pregnancy for women with type 1 diabetes. Diabetes Care. 2015 Jan;38(1):34-42. doi: 10.2337/dc14-1755. Epub 2014 Nov 3.

  PMID: 25368104 BACKGROUND

• Murphy HR, Bell R, Cartwright C, Curnow P, Maresh M, Morgan M, Sylvester C, Young B, Lewis-Barned N. Improved pregnancy outcomes in women with type 1 and type 2 diabetes but substantial clinic-to-clinic variations: a prospective nationwide study. Diabetologia. 2017 Sep;60(9):1668-1677. doi: 10.1007/s00125-017-4314-3. Epub 2017 Jun 8.

  PMID: 28597075 BACKGROUND

• Feig DS, Donovan LE, Corcoy R, Murphy KE, Amiel SA, Hunt KF, Asztalos E, Barrett JFR, Sanchez JJ, de Leiva A, Hod M, Jovanovic L, Keely E, McManus R, Hutton EK, Meek CL, Stewart ZA, Wysocki T, O'Brien R, Ruedy K, Kollman C, Tomlinson G, Murphy HR; CONCEPTT Collaborative Group. Continuous glucose monitoring in pregnant women with type 1 diabetes (CONCEPTT): a multicentre international randomised controlled trial. Lancet. 2017 Nov 25;390(10110):2347-2359. doi: 10.1016/S0140-6736(17)32400-5. Epub 2017 Sep 15.

  PMID: 28923465 BACKGROUND

• Tennant PW, Glinianaia SV, Bilous RW, Rankin J, Bell R. Pre-existing diabetes, maternal glycated haemoglobin, and the risks of fetal and infant death: a population-based study. Diabetologia. 2014 Feb;57(2):285-94. doi: 10.1007/s00125-013-3108-5. Epub 2013 Nov 29.

  PMID: 24292565 BACKGROUND

• Singh H, Murphy HR, Hendrieckx C, Ritterband L, Speight J. The challenges and future considerations regarding pregnancy-related outcomes in women with pre-existing diabetes. Curr Diab Rep. 2013 Dec;13(6):869-76. doi: 10.1007/s11892-013-0417-5.

  PMID: 24013963 BACKGROUND

• Singh H, Ingersoll K, Gonder-Frederick L, Ritterband L. "Diabetes Just Tends to Take Over Everything": Experiences of Support and Barriers to Diabetes Management for Pregnancy in Women With Type 1 Diabetes. Diabetes Spectr. 2019 May;32(2):118-124. doi: 10.2337/ds18-0035.

  PMID: 31168282 BACKGROUND

• Langer N, Langer O. Pre-existing diabetics: relationship between glycemic control and emotional status in pregnancy. J Matern Fetal Med. 1998 Nov-Dec;7(6):257-63. doi: 10.1002/(SICI)1520-6661(199811/12)7:63.0.CO;2-H.

  PMID: 9848689 BACKGROUND

• Berg M. Pregnancy and diabetes: how women handle the challenges. J Perinat Educ. 2005 Summer;14(3):23-32. doi: 10.1624/105812405X57552.

  PMID: 17273439 BACKGROUND

• Berg M, Honkasalo ML. Pregnancy and diabetes--a hermeneutic phenomenological study of women's experiences. J Psychosom Obstet Gynaecol. 2000 Mar;21(1):39-48. doi: 10.3109/01674820009075607.

  PMID: 10907214 BACKGROUND

• Gupton A, Heaman M, Cheung LW. Complicated and uncomplicated pregnancies: women's perception of risk. J Obstet Gynecol Neonatal Nurs. 2001 Mar-Apr;30(2):192-201. doi: 10.1111/j.1552-6909.2001.tb01535.x.

  PMID: 11308109 BACKGROUND

• Donovan LE, Lemieux P, Dunlop AD, Yamamoto JM, Murphy HR, Simmons D, Bell RC, Chaput KH, Benham JL, Ross GP, Nerenberg KA, Booth JE, Perkins BA, Mohammad K, Ntanda HN, King JA, Tomlinson G, Feig DS; CIRCUIT Collaborative Group. Closed-Loop Insulin Delivery in Type 1 Diabetes in Pregnancy: The CIRCUIT Randomized Clinical Trial. JAMA. 2025 Dec 23;334(24):2176-2185. doi: 10.1001/jama.2025.19578.

  PMID: 41134589 DERIVED

MeSH Terms

Conditions

Diabetes Mellitus, Type 1; Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Nutritional and Metabolic Diseases; Autoimmune Diseases; Immune System Diseases

Study Officials

• Lois Donovan, MD

  University of Calgary

  PRINCIPAL INVESTIGATOR

• Denice Feig, MD

  MOUNT SINAI HOSPITAL

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: MD

Study Record Dates

• First Submitted: April 28, 2021
• First Posted: May 26, 2021
• Study Start: June 15, 2021
• Primary Completion: May 23, 2025
• Study Completion: May 23, 2025
• Last Updated: June 5, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will not share

Locations

CA (9); AU (5)