A dense-sampling investigation of interoceptive variation across the menstrual cycle: the Cyclic Hormones and Interoception with Repeated Profiling (CHIRP) Study.

The menstrual cycle is associated with variation in psychological and sensory processing and can exert substantial influence on mental health. One process which may be impacted by hormonal fluctuations during the menstrual cycle is interoception - the process by which the nervous system senses, integrates, and models the internal state of the body. However, limited work has examined if and how interoception may change across the menstrual cycle and if these changes are associated with mental health outcomes. Additionally, outstanding questions surrounding the reliability and concordance of interoception measures over time hinder progress in understanding these associations. To address these limitations, the CHIRP study aims to provide an illustrative example in two participants of how measures of interoception may vary across the course of the menstrual cycle using a dense sampling approach that spans multiple organ systems and dimensions of interoception (e.g., self-report and task-based measures), focusing on associations between fluctuations in interoception and mood. The repeated measures will be analyzed using Generative Additive Models (GAMs) to assess fluctuations across the cycle. Ultimately, this project aims to provide insight into how reproductive hormones may shape interoceptive processing and generate hypotheses for future investigations of menstrual-cycle-related mental health risk.