Menstrual Cycle Mapping While Using Closed-Loop Insulin Delivery

The hypothesis is that menstrual cyclicity affects glucose and energy metabolism in women with type 1 diabetes. The rationale of the hypothesis on cycle effects builds on the assumption that fluctuations of female sex hormones across the menstrual cycle cause changes in physiological parameters of glucose metabolism and energy homeostasis and/or lifestyle aspects involved in the regulation of blood glucose and body weight. It is expected that hormone fluctuations affect insulin sensitivity, gastric emptying, eating behaviour and energy expenditure. It is anticipated that insulin sensitivity is highest in the pre-ovulatory phase and lowest in the mid-luteal phase. It is further expected that gastric emptying peaks in the follicular phase, and highest energy expenditure and dietary intake during the mid-luteal phase. The primary objective of this study is to characterize glucose and energy metabolism throughout the menstrual cycle in natural cycling women with type 1 diabetes. Further objectives are to assess the impact of the menstrual cycle on glucose control and insulin requirements, investigate how fluctuations in sex hormone levels influence glucose and energy metabolism, and quantify both inter- and intra-individual variability in metabolic changes related to the menstrual cycle. Additionally, the study will evaluate whether changes in key physiological components of glucose metabolism and behavioural factors mediate menstrual cycle-related variations in glucose control and insulin requirements.