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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.
Pregnant women with type 1 diabetes (T1D) require normal or near normal glucose in order to reduce the risks of birth defects, stillbirth, increased birthweight, neonatal hypoglycemia, neonatal death, preterm delivery and preeclampsia. Reducing maternal glucose is extremely difficult due to an increased risk of maternal hypoglycemia. Only 14% of T1D pregnancies achieve pregnancy guideline recommended glucose control, leading to complications related to high maternal glucose exposure in roughly half of newborns.
Maintaining recommended maternal glucose levels during pregnancy reduces the risk of adverse neonatal outcomes to those similar in pregnancies unaffected by T1D. Most insulin pumps in use today are open-loop systems, which means that the user must program the pump to deliver a pre-set amount of insulin. These insulin delivery methods (MDI and open-loop pumps) are usually inadequate to achieve the optimal glucose control necessary for T1D pregnancies and they impart a large time, effort and emotional burden.
Closed-loop systems have been found to be effective in improving glucose control outside of pregnancy when studied in children and adults. A new hybrid closed-loop system, the Tandem t:slim X2 insulin pump with Control IQ technology, recently became commercially available. Trials have demonstrated the efficacy of the Control IQ algorithm for non-pregnant adults and children. Pregnant women were not included in these trials.
The investigators propose the first randomized controlled trial to evaluate the Tandem t:slim X2 insulin pump with Control IQ technology versus standard insulin delivery (MDI or pump) and CGM in pregnant women with T1D. In this trial, the investigators 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.
We are grateful to Tandem Diabetes Care and Dexcom for in-kind donations to this investigator initiated study.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| 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. |
|
| 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. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 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. |
| Measure | Description | Time Frame |
|---|---|---|
| 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 |
| Measure | Description | Time Frame |
|---|---|---|
| Percent time spent above target range per day (+/-SD) | Glucose above target range defined as glucose >7.8 mmol/L; Blood glucose will be assessed using CGM data | 16 weeks gestation until delivery of neonate |
| Percent time spent below target range per day (+/-SD) |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Lois Donovan, MD | University of Calgary | Principal Investigator |
| Denice Feig, MD | MOUNT SINAI HOSPITAL | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Campbelltown Hospital | Campbelltown | 2560 | Australia | |||
| Royal Prince Alfred Hospital |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 19675195 | Background | 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. | |
| 24705609 | 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. |
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Glucose below target range defined as glucose < 3.5 mmol/L; Blood glucose will be assessed using CGM data |
| 16 weeks gestation until delivery of neonate |
| Mean blood glucose measurement at 24 and 34 weeks (+/-SD) | Blood glucose measured in mmol/L and assessed using CGM data | 24 and 34 weeks gestation |
| Proportion of participants who experience maternal hypoglycemic events | Maternal hypoglycemic events defined as ≥15 minutes with CGM glucose <3.5 mmol/L [level 1] or <2.8 mmol/L [level 2]; Blood glucose will be assessed using CGM data | 16 weeks gestation until delivery of neonate |
| Glycemic variability reflected by the coefficients of variation and standard deviations of CGM data | Blood glucose measured in mmol/L and assessed using CGM data | 16 weeks gestation until delivery of neonate |
| Diabetes-related distress to the participant | Diabetes-related distress will be assessed four times during the study using the Diabetes Distress Screening Scale (DDSS17) | 7-13 weeks + 6 days gestation, 24 weeks gestation, 34 weeks gestation, 6 weeks postpartum |
| Fear of hypoglycemia | Fear of hypoglycemia will be assessed four times during the study using the Hypoglycemia Fear Survey Questionnaire II (HFSQ II) | 7-13 weeks + 6 days gestation, 24 weeks gestation, 34 weeks gestation, 6 weeks postpartum |
| Fear of hyperglycemia | Fear of hyperglycemia will be assessed four times during the study using the g. Hyperglycemia Fear in Pregnancy Survey | 7-13 weeks + 6 days gestation, 24 weeks gestation, 34 weeks gestation, 6 weeks postpartum |
| Sleep quality | Sleep quality will be assessed at four times during the study using the Modified Pittsburgh Sleep Quality Index (PSQI) | 7-13 weeks + 6 days gestation, 24 weeks gestation, 34 weeks gestation, 6 weeks postpartum |
| Health-related quality of life | Health-related quality of life will be assessed four times during the study using the Euro Quality of life questionnaire (EQ-5D-5L) | 7-13 weeks + 6 days gestation, 24 weeks gestation, 34 weeks gestation, 6 weeks postpartum |
| Work productivity | Work productivity will be assessed four times during the study using the Work Productivity and Activity Impairment survey | 7-13 weeks + 6 days gestation, 24 weeks gestation, 34 weeks gestation, 6 weeks postpartum |
| Diabetes-related distress to the partners | Diabetes-related distress to the partners will be assessed four times during the study using the Partner Diabetes Distress Scale | 7-13 weeks + 6 days gestation, 24 weeks gestation, 34 weeks gestation, 6 weeks postpartum |
| Proportion of participants who experience preeclampsia events | Preeclampsia is defined as pregnancy ≥20 wks gestation with SBP ≥140mmHg and/or DBP ≥90 mmHg on ≥2 occasions a minimum of 6 hrs apart and new-onset of proteinuria (defined as urinary excretion ≥0.3g protein on a 24-hr urine specimen, or ≥ 2+ by urinary dipstick, or ≥30mg protein/mmol of urinary creatinine by spot testing) OR ≥1 of the following adverse conditions:
| 16 weeks gestation until delivery of neonate |
| Proportion of participants who experience gestational hypertension events | Gestational hypertension is defined as a woman ≥20 weeks gestation with a systolic blood pressure of ≥140 mm Hg and/or a diastolic blood pressure ≥90 mm Hg on ≥2 occasions a minimum of 6 hours apart without proteinuria | 16 weeks gestation until delivery of neonate |
| Proportion of participants who experience worsening chronic hypertension events | Chronic hypertension is defined as hypertension that is present at <20 weeks gestation or pre-pregnancy | 16 weeks gestation until delivery of neonate |
| Proportion of participants who have caesarean deliveries | 16 weeks gestation until delivery of neonate |
| Proportion of participants who experience preterm births | Preterm birth defined as birth occurring <37 weeks gestation | Delivery of neonate to 6 weeks postpartum |
| Proportion of babies born large for gestational age (>90th percentile) | Delivery of neonate |
| Proportion of babies born small for gestational age (<10th percentile) | Delivery of neonate |
| Mean neonatal birthweight (+/-SD) | Birthweight measured in kilograms | Delivery of neonate |
| Comparison of birthweight z-score | Delivery of neonate |
| Proportion of babies born with neonatal hypoglycemia | Delivery of neonate |
| Proportion of neonates admitted to intensive care unit admission | Admission to neonatal intensive care unit admission defined as admission of 24 hours or more | Delivery of neonate to 6 weeks postpartum |
| Proportion of participants who experienced pregnancy loss or miscarriage (< 20 weeks, stillbirth ≥20 weeks, neonatal loss up to 28 days) | 7-13 weeks until delivery of neonate + up to 28 days |
| Proportion of participants who experience episodes of severe hypoglycemia | Severe hypoglycemia defined as a hypoglycemic episode requiring assistance from another person. | 7-13 weeks + 6 days gestation until delivery of neonate |
| Proportion of participants who experience episodes of diabetic ketoacidosis | Diabetic ketoacidosis (DKA) is defined as an episode with elevated plasma ketones which can be categorized as possible DKA (mild/ self- treated [plasma ketones 0.6 - 1.5mmol/L], moderate/self-treated (plasma ketones > 1.5mmol/L which resolves without hospital admission), or capillary blood ketones >3.0 mol/L without an anion gap of > 15 with admission to hospital for another reason [i.e. prevention of DKA]) or confirmed DKA (severe, with either plasma ketones > 3.0mmol/L or positive serum ketones with an anion gap (Na -(CI+HC03) > 15 and requiring hospital admission for IV fluids and IV insulin to correct the abnormal metabolic state). | 7-13 weeks + 6 days gestation until delivery of neonate |
| Proportion of participants who experience device-related adverse events | Device-related adverse events include skin reactions and insulin delivery failures. | 7-13 weeks + 6 days gestation until delivery of neonate |
| Camperdown |
| Australia |
| Canberra Hospital | Garran | Australia |
| Royal Women's Hospital | Parkville | Australia |
| Westmead Hospital | Westmead | Australia |
| University of Calgary | Calgary | Alberta | T2T 5C7 | Canada |
| BC Women's Hospital | Vancouver | British Columbia | Canada |
| University of Manitoba | Winnipeg | Manitoba | R3E 3P4 | Canada |
| IWK Health Centre | Halifax | Nova Scotia | B3K 6R8 | Canada |
| Lawson Health Research Institute | London | Ontario | N6C 2R5 | Canada |
| Sunnybrook | Toronto | Ontario | M4N 3M5 | Canada |
| Mount Sinai Hospital | Toronto | Ontario | M5T 3L9 | Canada |
| University of Montreal - CHUM | Montreal | Quebec | H2X 3J4 | Canada |
| Université Laval | Québec | Quebec | G1V 4G2 | Canada |
| 15066886 | 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. |
| 21115765 | 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. |
| 25368104 | 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. |
| 28597075 | 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. |
| 28923465 | 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. |
| 24292565 | 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. |
| 24013963 | 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. |
| 31168282 | 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. |
| 9848689 | 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. |
| 17273439 | Background | Berg M. Pregnancy and diabetes: how women handle the challenges. J Perinat Educ. 2005 Summer;14(3):23-32. doi: 10.1624/105812405X57552. |
| 10907214 | 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. |
| 11308109 | 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. |
| 41134589 | Derived | 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. |
| ID | Term |
|---|---|
| D003922 | Diabetes Mellitus, Type 1 |
| D044882 | Glucose Metabolism Disorders |
| D008659 | Metabolic Diseases |
| D004700 | Endocrine System Diseases |
| ID | Term |
|---|---|
| D003920 | Diabetes Mellitus |
| D009750 | Nutritional and Metabolic Diseases |
| D001327 | Autoimmune Diseases |
| D007154 | Immune System Diseases |
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