Table S1: We defined RPTs as the range between the pain tolerance and the pain threshold (RPT= pain tolerance-pain threshold) and found a significant correlation between pain threshold and pain tolerance in both the emF and mL phases Table S2: There was no significant difference in the RPT between the emF and mL phase Table S3: Relationship between pain perceptionrc and sex hormonerc by correlation analysis Figure S1: The phase-specific ultrasound imaging features were as follows: the follicular phase was indicated by the appearance of dominant follicles and a thin homogenous echo in the endometrium; ovulation was indicated by the first appearance of dominant follicles measuring 16 to 28 mm in diameter, with their subsequent disappearance with or without detectable fluid in the pouch of Douglas; and after ovulation, the luteal phase was indicated by an thick endometrial Figure S2: Relationship between sex hormonesrc and pain perceptionrc