Intrapartum and Early Postpartum Use of Automated Insulin Delivery in Type 1 Diabetes: A Prespecified Analysis of the CIRCUIT Randomized Controlled Trial.

OBJECTIVE

Following the demonstrated improvement in pregnancy glycemia with Control-IQ closed loop in the Closed-Loop Insulin Delivery by Glucose Responsive Computer Algorithms in Type 1 Diabetes Pregnancies (CIRCUIT) trial, we compared intrapartum and early postpartum glycemic effectiveness and safety with standard care in type 1 diabetes.

RESEARCH DESIGN AND

METHODS

The primary outcome of this prespecified analysis was percentage of time in pregnancy-specific glucose range (63-140 mg/dL) during the 24 h prior to childbirth, measured by continuous glucose monitoring. A key secondary outcome was percentage of time at <70 mg/dL in the first postpartum week, with additional secondary outcomes including continuous glucose monitoring metrics through 6 weeks postpartum. Analyses were adjusted for baseline measure, insulin delivery mode, and site.

RESULTS

In the intrapartum period (24 h before delivery), 39 of 44 (89%) participants continued closed loop. Intravenous insulin was used intrapartum by one (2%) closed-loop participant and 20 (45%) standard-care participants (P < 0.001). Intrapartum closed-loop users spent more time in pregnancy-specific glucose range (79.6% vs. 64.8%) than the standard-care group (mean adjusted difference 13.2 percentage points; 95% CI 5.2, 21.2). In the first postpartum week, the closed-loop group spent less time <70 mg/dL (1.7% vs. 3.2%; mean adjusted difference -1.8 percentage points; 95% CI -0.9 to -2.7) compared with the standard-care group. No maternal severe hypoglycemia occurred in the closed-loop group, while one episode occurred in the standard-care group postpartum. No diabetic ketoacidosis occurred in either group.

CONCLUSIONS

Use of this closed-loop system resulted in superior intrapartum and early postpartum glycemia compared with standard care without safety concerns. Together with previous results, this supports use of this closed-loop system throughout pregnancy, labor, and the early postpartum period.