An interventional study of Tandem t:slim X2 insulin pump with Control IQ technology in Type 1 Diabetes Mellitus, Pregnancy Related and Glucose Metabolism Disorders, sponsored by University of Calgary. Completed at 14 sites in 2 countries. Open to female participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2025-06-05.
Sponsored by University of Calgary · Not applicable, Interventional, and Treatment
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.
149 studies on the registry are indexed under Pregnancy in Diabetics; 33 are open to participants now.
This study's enrollment of 94 is close to the median of 90 across 88 interventional studies indexed under Pregnancy in Diabetics.
Browse Pregnancy in Diabetics studies →University of Calgary is the lead sponsor of 686 studies on the registry; 189 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 2 (20%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
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
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.
The intervention group will be fitted with the Tandem t:slim X2 insulin pump with Control IQ technology during pregnancy.
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
Time frame: 16 weeks until 34 weeks gestation
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
Time frame: 16 weeks gestation until delivery of neonate
Percent time spent below target range per day (+/-SD)
Glucose below target range defined as glucose \< 3.5 mmol/L; Blood glucose will be assessed using CGM data
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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)
Time frame: 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)
Time frame: 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
Time frame: 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)
Time frame: 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)
Time frame: 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
Time frame: 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
Time frame: 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: * Eclampsia (Seizures in pregnancy) * Elevated liver function tests (Increased AST and/or ALT \>70 IU/L) * Decreased platelet count \<100 x 109/L * Elevated serum creatinine (\>80 μmol/L) * Small for gestational age infant (birth weight \<10th percentile)
Time frame: 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
Time frame: 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
Time frame: 16 weeks gestation until delivery of neonate
Proportion of participants who have caesarean deliveries
Time frame: 16 weeks gestation until delivery of neonate
Proportion of participants who experience preterm births
Preterm birth defined as birth occurring \<37 weeks gestation
Time frame: Delivery of neonate to 6 weeks postpartum
Proportion of babies born large for gestational age (>90th percentile)
Time frame: Delivery of neonate
Proportion of babies born small for gestational age (<10th percentile)
Time frame: Delivery of neonate
Mean neonatal birthweight (+/-SD)
Birthweight measured in kilograms
Time frame: Delivery of neonate
Comparison of birthweight z-score
Time frame: Delivery of neonate
Proportion of babies born with neonatal hypoglycemia
Time frame: 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
Time frame: 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)
Time frame: 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.
Time frame: 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).
Time frame: 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.
Time frame: 7-13 weeks + 6 days gestation until delivery of neonate
Plan to share: No
This study is completed, as verified in Jun 2025. You cannot join it, but the record below documents what was studied.
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University of Calgary