Changes in sex hormones and their interactions are related to pain perception between different menstrual subphases.

Abstract

Background Whether sex hormones are related to pain perception across the menstrual cycle is unclear. We examined changes in experimental pain perception in healthy young females between the early-to mid-follicular subphase (emF) and the mid-luteal subphase (mL) and explored the role of sex hormones. Methods 66 participants were finally involved in the study. We tested pressure pain, cold pain, ischemic pain and needle pain meanwhile measured sex hormones levels in two menstrual subphases. Results Only the right ulna pressure test showed a significant reduction in pain threshold (PPTh3) during the mL. The absolute change of PPTh3 (PPTh3mL -PPTh3emF) was related to the absolute change of prolactin. The relative change of the range of pain tolerance for pressure pain of the right ulna (RPT3rc) was related to the relative change of progesterone (Prc) and estradiol(E2rc) levels, and the interaction effects showed that at Prc≤30, E2rc was positively correlated with RPT3rc. The same, the relative change of pressure pain tolerance of the pulp of the middle finger on the right hand (PPTo4rc) was related to E2rc and Prc, and the results of the interaction between E2rc and Prcsuggest that when E2rc is ≤0.8, Prc is positively correlated with PPTo4rc. Conclusions Two different formulas were applied in this study and showed inconsistent results. Most pain tests showed no difference between two subphases of menstrual cycle. Only the relative changes of the PPTo4 and RPT3 are related to the E2rc and Prc respectively between menstrual subphase in an interactive way in healthy young women.