American Diabetes Association
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A Randomized Trial of Closed-Loop Insulin Delivery Postpartum in Type 1 Diabetes

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posted on 2023-10-12, 19:16 authored by Lois E Donovan, Denice S. Feig, Patricia Lemieux, Helen R. Murphy, Rhonda C. Bell, Ronald J. Sigal, Josephine Ho, Heidi Virtanen, Susan Crawford, Jennifer M Yamamoto


This study aimed to evaluate the efficacy of closed-loop insulin delivery postpartum.


In this open-label, randomized controlled trial, postpartum individuals with type 1 diabetes were randomized to hybrid closed-loop insulin delivery with the MiniMed™ 670G/770G system in auto-mode or sensor augmented pump therapy, in the first 12-weeks postpartum followed by a continuation phase with closed-loop for all until 24-weeks postpartum.


Eighteen participants (mean±SD age 32±3.5 years, diabetes duration 22±7.3 years and early pregnancy HbA1c 52±6.8 mmol/mol [6.9±0.9%]) completed 24-weeks of postpartum follow-up. In the randomization phase, percent time in range, 70-180 mg/dL (3.9-10 mmol/L) did not differ between groups (79.2±8.7% versus 78.2±6.0%; p=0.41). Women randomized to closed-loop spent less time below 70 mg/dL (3.9 mmol/L) and 54 mg/dL (3.0 mmol/L) (1.7±0.8% versus 5.5±3.3%; p<0.001 and 0.3±0.2% versus 1.1±0.9%; p=0.008). Time above 180 mg/dL (10 mmol/L) was not different between groups (18.7±8.8% versus 15.9±7.7%; p=0.21). In the continuation phase, those initially randomized to sensor augmented pump had less time below 70 mg/dL after initiation of closed-loop (5.5±3.3% versus 3.3±2.2%; p=0.039). The closed-loop group maintained similar glycemic metrics in both study phases. There were no episodes of diabetic ketoacidosis or severe hypoglycemia in the randomized or continuation phase in either group.


Women randomized to closed-loop insulin delivery postpartum had less hypoglycemia than those randomized to sensor augmented pump therapy. There were no safety concerns. These findings are reassuring for use of closed-loop insulin delivery postpartum because of its potential to reduce hypoglycemia.


This study was funded by the Calgary Health Trust. Medtronic provided in-kind support of Guardian Link 3 transmitters and Guardian Sensor (3) sensors, and loan of study devices, MiniMed 670G and 770G insulin pumps and transmitter docks. The funders of the study had no role in the study design, data collection, data analysis, or data interpretation. Medtronic reviewed the manuscript prior to submission for correctness of the description of their products.


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