Pregnant women need appropriate glycemic management to maintain maternal and fetal wellbeing during gestation. The aim is to avoid complications, especially due to hypoglycemia which can be a problem for expectant mothers who have Type 1 diabetes (T1D). Subcutaneous insulin injections and continuous glucose monitors are not FDA-approved for usage during pregnancy. Therefore, alternative options need to be explored. 

A small cohort study of pregnant females showed that closed-loop insulin delivery could be effective in keeping glucose levels in check. This procedure is beneficial for pregnancy complicated by T1D and comes in handy. 

Eyal Dassau and colleagues at the Harvard John A. Paulson School of Engineering and Applied Sciences at Harvard University conducted a small study to test the closed-loop insulin delivery and its effect on time in range. The study group had 11 pregnant women (14-32 weeks gestation) with T1D, comparing a 1-week run-in phase to a 2-day closed-loop control intervention. During the run-in phase, participants used a Dexcom G6 CGM and their personal insulin pump at home. In the next phase, participants switched to an  insulin pump supplied by the institution.

Results revealed a considerable difference in the time-in range between the run-in phase and the closed-loop control supervised sessions. The time-in range during run-in phase increased from 64% to 81.5% during the closed-loop phase. Variations in blood glucose levels were less during the supervised phase. Time in hyperglycemia (>140 mg/dL) decreased from 30.8% during the run-in to 16.5% during the supervised session. Moreover, the time in hypoglycemia (<63 mg/dL) changed from 5.2% to 2% in supervised sessions. 

The results were encouraging for the effective management of blood glucose levels through closed-loop control but this still is based on a very small sample. More research is needed to confirm that this is a safe approach for managing type 1 diabetes during pregnancy.