Many women with type 1 diabetes report difficulty with managing their blood glucose at certain phases of their menstrual cycle. Research, although conflicting, suggests that this might be due to changes in insulin sensitivity in a subset of women with type 1 diabetes.
This study was another subanalysis of the iDCL (International Diabetes Closed-Loop) trial of a hybrid closed-loop insulin delivery system, described in our other Digest this month. The aim was to evaluate glycaemic outcomes over the menstrual cycle in women using the closed-loop system. A total of 16 women had data available over an average of 6 cycles, with an average of 145 days of data analysed per participant.
Mean 24-hour glucose in the participants was 8.9 mmol/L during the menstrual phase, 9.2 mmol/L in the luteal phase and 8.8 mmol/L during the rest of the cycle. Mean time in range was stable, at 67–69%, throughout. No changes in automated or user-controlled insulin delivery were observed throughout the cycles.
The hybrid closed-loop system used in this study has previously been shown to improve overall time in range in people with type 1 diabetes (Brown et al, 2019). These data suggest that this remains the case irrespective of menstrual cycle phase, and they add to a growing body of work to optimise glycaemic control in menstruating women.
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9 Nov 2023