Closed-loop Insulin Delivery in Pregnant Women With Type 1 Diabetes

Closed-loop Insulin Delivery in Pregnant Women With Type 1 Diabetes: a Randomized Controlled Trial: the CRISTAL Study

Multi-centric open-label randomized controlled trial (RCT) with 11 Belgian centers and one Dutch center in pregnant women with type 1 diabetes to assess safety, efficacy, feasibility and cost-effectiveness of 780 MiniMed Medtronic hybrid closed-loop insulin system (intervention group) compared to standard of care therapy (control group).

Women will be recruited with a singleton pregnancy up to 12 weeks gestation. Participants will be randomized 1/1 to 780 pump or standard of care (continue with current treatment of insulin pump without closed-loop or multiple daily insulin injections). Participants will be stratified according to study center, baseline Hba1c, and method of insulin delivery (pump or injections). Participants will be followed-up till delivery. To account for differences in the type of continuous glucose monitoring (CGM) used between the intervention group and the control group, the same CGM system as in the 780 insulin pump group (Guardian™ Sensor 3 and once available the Guardian 4 sensor) will be used in a blinded manner in the control group to collect CGM data during at least four different time points in pregnancy: at 14-17 weeks, 20-23 weeks, 26-29 weeks and 33-36 weeks.

Inclusion Criteria:

• Women with type 1 diabetes (T1DM), diagnosed with T1DM at least 1 year before pregnancy
• Age 18-45 years
• A singleton pregnancy confirmed by b-HCG in blood and/or ultrasound-confirmed gestational age up to 11 weeks and 6 days.
• Treated with intensive insulin treatment (either MDI or insulin pump). A closed-loop system can only be used in manual mode.
• Have a booking HbA1c (measurement taken at the first antenatal clinic visit after confirmed pregnancy) level ≤10%.
• Participants need to speak and understand Flemish, French or English and have e-mail access.

Exclusion Criteria:

• The use of a closed-loop insulin delivery system in auto mode.
• A twin (multiple) pregnancy
• A physical or psychological disease likely to interfere with the conduct of the study (based on the evaluation by the treating physician)
• Medications known to interfere with glucose metabolism
• An insulin dose of ≥1.5 units/kg
• Known allergy to adhesives due to infusion set and/or CGM