Objective : MiniMed® 670G insulin pump by Medtronic offers first and only hybrid closed loop system for insulin delivery currently available in the market. This pump provides safe and efficacious way of delivering continuous insulin in type 1 diabetes patients. The safety for its use during pregnancy in mothers with type 1 diabetes has not been established and therefore it is not approved currently for its use in pregnancy. We present a case of a patient with type 1 diabetes who was continued on auto-mode during her pregnancy safely.
Methods : A 37 year old female with history of type 1 diabetes presented to endocrinology clinic for ongoing management of her diabetes on insulin pump. Patient had been on MiniMed® 670G insulin pump with sensor using the auto-mode prior to her pregnancy. She insisted to continue her auto-mode while she remained pregnant despite counseling that it is not approved for use in pregnancy. Patient was followed every 4 weeks until delivery.
Results : She remained on auto-mode 80% to 100% of the time as evident with each pump download during her pregnancy. Her most recent hemoglobin A1c was noted to be 6.3%. Her insulin to carb ratio was at 1: 6, insulin sensitivity was 70 and the target for her blood glucose was kept at 100-120 mg/dl. Her basal rate was 0.475 units per hour for all 24 hours. Patient reported to check her blood glucose 4 times daily and did wear her sensor 80% to 100% of the time during her pregnancy. She was 95% within target range during her most recent pump download before delivery. She had hypoglycemia only 2% of the time with blood glucose ranging 50-70 mg/dl. Her average blood glucose was 117 mg/dl.
Discussion : This patient’s use of auto-mode with a closed hybrid loop system insulin pump during pregnancy exemplifies that off label use for select patients with type 1 diabetes may prove to be beneficial. Pregnancy demands a tighter control for blood glucose with a target blood glucose close to 100 mg/dl. This can be more efficiently and safely achieved with the auto-mode use of insulin pump. Patient delivered healthy twins via c-section. She did have pre-eclampsia without any severe features ending with safe delivery of the twins.
Conclusion : Mothers with type 1 diabetes have a high-risk pregnancy and controlling their blood glucose is essential. Further studies are needed to establish safety of the auto-mode on 670G® Mini-med during pregnancy. However, such cases showcase the use of auto-mode to be beneficial in patients with type 1 diabetes who typically have variable and difficult to control blood glucose.
University of Florida Department of Medicine
Endocrinology Fellow at University of Florida Jacksonville