We performed a parallel, two-site, randomized controlled trial of a commercially available hybrid closed-loop (HCL) system compared to sensor augmented pump therapy (SAPT) in pregnant women with type 1 diabetes (T1D). Participants started SAPT (Medtronic 670G) by 11 weeks gestation, were randomized at 14-18 weeks, and continued therapy until 6 weeks postpartum. The HCL group used assistive techniques, “fake carbohydrate” boluses, to optimize therapy. We performed linear mixed model regression to compare outcomes between groups, adjusted for clinic. There were 24 women randomized and 23 completers. At baseline there were no significant differences between groups (mean baseline A1C 6.8% at 8w5d [SAPT]/9w0d [HCL] enrollment). There were no episodes of severe hypoglycemia or diabetic ketoacidosis after randomization. Adverse skin reactions occurred in 6 participants (5 SAPT vs 1 HCL, p=0.1550) with a median (IQR) number of 1 (1-2) SAPT vs 4 (4-4) HCL (p=0.8774). A1C significantly decreased from baseline to 2nd trimester, and was different between groups in the 3rd trimester (Table 1). There were no differences in time below, within, or above range between groups during the study (Table 1) or in gestational health outcomes (Table 2). In a pilot cohort of pregnant women with T1D, assisted HCL therapy did not increase risk to mothers or fetuses compared to SAPT despite lack of a pregnancy-specific algorithm in the HCL system.

Disclosure

E.Buschur: Consultant; Beta Bionics, Inc., Research Support; Dexcom, Inc., JDRF, Leona M. and Harry B. Helmsley Charitable Trust. E.R.Nease: None. S.Polsky: Other Relationship; diaTribe, Research Support; Dexcom, Inc., Medtronic, Hemsley Charitable Trust, JDRF, NIH - National Institutes of Health. J.K.Snell-bergeon: None. L.Pyle: None. R.Garcetti: None. K.M.Dungan: Board Member; Elsevier, Consultant; Eli Lilly and Company, Dexcom, Inc., Other Relationship; UpToDate, Research Support; Dexcom, Inc., Abbott, ViaCyte, Inc., Sanofi, Speaker's Bureau; Academy for Continued Healthcare Learning, Cardiometabolic Health Congress, Medscape, Integritas. S.F.Thung: None. A.Bartholomew: None. T.Summerfield: None. T.Bloks: None.

Funding

JDRF (2-SRA-2018-666-M-R); Colorado Clinical and Translational Sciences Institute; Children’s Diabetes Foundation; National Center for Research Resources (UL1RR02578)

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