Case series of a hybrid closed loop therapy system used in pregnancy.

Aims: The effectiveness of Hybrid Closed-Loop (HCL) therapy is rarely studied in type 1 diabetes (T1D) pregnancies.

Methods: T1D pregnancies (n = 15) managed off-label during gestation using a commercially available HCL system, Tandem Control IQ, were retrospectively reviewed for baseline characteristics, continuous glucose monitoring (CGM), insulin pump use, insulin doses, and gestational health outcomes. Analyses for unadjusted descriptive statistics of baseline characteristics, glycemic parameters, and gestational health outcomes were performed (mean ± standard deviation (SD) or median with interquartile range (IQR) for continuous variables). Control IQ was used prior to pregnancy by 12 of the 15 cases, with 3 initiating use during gestation.

Results: On average, targets were met for pregnancy-specific Time-In-Range (psTIR, 63-140 mg/dL for > 70%) during most of gestation, pregnancy-specific Time-Below-Range (psTBR, < 63 mg/dL for < 4%) throughout gestation, and pregnancy-specific Time-Above-Range (psTAR, > 140 mg/dL for < 25%) from 10- to 17-week gestation. Targets for non-pregnancy TIR (70-180 mg/dL), TAR (> 140 mg/dL), and TBR (< 70 mg/dL) were met preconception and post-partum. Glycemic metrics improved after the first pregnancy visit wherein assistive techniques were applied for off-label use of this HCL system. Gestational health outcomes were as anticipated for T1D pregnancies.

Conclusions: Tandem Control IQ HCL therapy used with assistive techniques in 15 T1D pregnancies was associated with improved glycemic levels from the first clinic visit onward.