Closed-Loop Insulin Delivery During Pregnancy in Women With Type 1 Diabetes EDITORIAL COMMENT

In women with diabetes mellitus (DM) and pregnancy, congenital anomalies have been shown to be associated with poor glycemic control around the time of conception. In addition, other complications are associated with maternal hyperglycemia throughout pregnancy. Unfortunately, the hormones of pregnancy lead to increasing insulin resistance that changes throughout pregnancy. Hence, pregnant women with type 1 DM(T1DM) face particular challenges in trying to maintain tight glycemic control. Closed-loop (automated) insulin delivery is shown to provide better glycemic control than sensor-augmented pump therapy in nonpregnant patients. However, there are insufficient data regarding the efficacy, safety, and feasibility of closed-loop therapy during pregnancy. An open-label, randomized, crossover study comparing overnight closed-loop therapy with sensor-augmented pump therapy was conducted. This was followed by a continuation phase in which the closed-loop system was used day and night. Participants of this study included 16 pregnant women with T1DM(between 18 and 45 years of age, with a pregnancy between 8 and 24 weeks of gestation and a glycated hemoglobin level between 6.5% and 10.0%) who completed 4 weeks of closed-loop pump therapy (intervention) and sensor-augmented pump therapy (control) in random order. The study found that, during the continuation phase, 14 of the participants used the closed-loop system day and night until delivery. Primary outcome was the percentage of time that overnight glucose levels were within the target range (63-140 mg/dL [3.5-7.8 mmol/L]). Results of the study revealed that the percentage of time that overnight glucose levels were in the target range was higher during closed-loop therapy than during control therapy (74.7% vs 59.5%; P = 0.002). Also, overnight mean glucose level was lower during closed-loop therapy than during control therapy (119 vs 133 mg/dL, P = 0.009). Data revealed that there were no significant differences between closed-loop and control therapy in the percentage of time in which glucose levels were below the target range (1.3% and 1.9%, respectively; P = 0.28), in insulin doses, or in adverse event rates. It was also noted that during the continuation phase (up to 14.6 additional weeks, including antenatal hospitalizations, labor, and delivery) glucose levels were in the target range 68.7% of the time; the mean glucose level was 126 mg/dL. There were no reports of severe hypoglycemia requiring third-party assistance at any time. This study concludes that overnight closed-loop therapy, as compared with sensor-augmented pump therapy, improved glucose control during pregnancy in women with T1DM. Also, during the continuation phase, women receiving day-and-night closed-loop therapy maintained glycemic control during a high percentage of the time in a period that encompassed antenatal hospital admission, labor, and delivery.