Continuous glucose monitoring (CGM) has highlighted the gap that exists between our expectations of tight metabolic control and the realities of achieving this, during type 1 diabetes pregnancy. Longitudinal measurements indicate that despite overall “good” HbA1c levels, pregnant women with type 1 diabetes spend 12 hours per day with glucose levels outside the recommended targets. New closed-loop (CL) or artificial pancreas approaches may help more women to safely achieve the recommended glucose targets. 

We have completed proof-of-concept studies evaluating overnight CL, in early (12-16 weeks) and late (28-32 weeks) gestation demonstrating near-normal overnight glucose control (85-100% time within target (3.5-7.8mmol/l or 73-140mg/dl), during early and late gestation. In a subsequent 24-hour crossover study comparing CL vs. SAP, CL achieved excellent overnight control (95-100% time in target), with 80% overall time in target, during meals, snacks and physical activity.

Home studies evaluating the feasibility, safety and efficacy of overnight and 24/7 CL in clinical settings are underway. Early data suggest that CL can be used equally safely and effectively by pump and MDI users and by CGM experienced and CGM naïve participants. CL has also been used during in-patient admissions to hospital maternity units, to maintain glucose control following antenatal steroids for fetal lung maturation as well as before, during and after delivery.

CL has superior efficacy to the gold standard sensor augmented pump therapy. Definitive proof of clinical efficacy, with user friendly devices, over longer duration and across a wider range of representative patients and clinics is now needed.