Differences in Experimental Pain Perception Across the Menstrual Cycle

Introduction: Pain is one of the common causes for which people seek medical help. Perception of pain is highly subjective as it is modulated by many endogenous physical and psychological factors. Many studies have shown that pain perception is gender specific. In the present study, it is observed how pain perception varies across different phases of the menstrual cycle. Materials and methods: Eighty-one normally menstruating females (17–25 years) were subjected to experimental pain of cold pressor task on days 1, 7, 14, and 21 of their menstrual cycle, and <i>pain threshold</i> (when the subject first reported feeling pain) and <i>pain tolerance</i> (maximum time subject tolerated the pain after immersion of hand in cold water) were measured (in seconds). Data were analyzed by one-way analysis of variance (ANOVA) with <i>post-hoc</i> Tukey's Honestly Significant Difference (HSD) test using appropriate software. Results: Mean pain threshold (seconds) were on day 1 (menstruation) (18.1 ± 5.5), day 7 (follicular phase) (14.7 ± 4.1), day 14 (ovulation phase) (9.8 ± 2.8), and day 21 (luteal phase) (16 ± 4.1), respectively, and mean pain tolerance (seconds) were on day 1 (108 ± 35.9), day 7 (87.1 ± 26.2), day 14 (65.1 ± 13.4), and day 21 (98.7 ± 30.5) of the menstrual cycle. It was observed that both pain threshold and pain tolerance showed variation across the menstrual cycle, statistically significant (<i>p</i> ≤ 0.001).