Switzerland: Real-world data show that glycemic control, insulin sensitivity, and insulin requirements fluctuate across different phases of the menstrual cycle in women with type 1 diabetes. To address this gap, Stefanie Hossmann from the Diabetes Center Berne, Switzerland, and colleagues investigated how menstrual cycle phases influence insulin sensitivity, insulin requirements, and glycemic control in adults with type 1 diabetes using AID systems. Participants self-enrolled and shared anonymized continuous glucose monitoring (CGM) data, insulin delivery records, carbohydrate intake, and menstrual cycle information. The researchers compared glucose control and insulin requirements across different menstrual cycle phases and estimated insulin sensitivity using a hierarchical Bayesian state-space model based on CGM data. Overall, the study confirms that insulin sensitivity, insulin requirements, and glycemic control vary across menstrual cycle phases.