Open-source automated insulin delivery systems for the management of type 1 diabetes during pregnancy.

A 40-year-old woman used an open-source automated insulin delivery system to manage her type 1 diabetes (T1D) prior to conception. The code for building the iPhone application called 'Loop' that carried the software for the hybrid closed-loop controller was available online. Her glycated hemoglobin before conception was 6.4%. Between 6 and 12 weeks gestation, she spent 66% time-in-range (TIR), 28% time-above-range (TAR) and 6% time-below-range (TBR). Between 18 and 24 weeks gestation, she spent 68% TIR, 27% TAR and 5% TBR. During her third trimester, she spent 72% TIR, 21% TAR and 7% TBR. She delivered a healthy infant with no neonatal complications. Clinicians should be aware of this technology as it gains traction in the T1D community and seeks Food and Drug Administration approval.