Dysmenorrhea, Menstrual Cycle Phase, and Previous Childbirth Pain Experience Responsiveness to Laboratory Pain

Abstract

The present studies were designed to investigate responsiveness of women to laboratory pain. The purpose of this investigation was manifold in that the effects of several different variables on pain perception were examined. First, the studies sought to determine whether the experience of menstrual pain, otherwise known as dysmenorrhea, had any relationship to the perception of laboratory induced pain, namely, cold pressor pain. Second, it was asked whether menstrual phase had any relationship either on its own, or in interacting with dysmenorrhea, to pain perception. Third, based on observations from the two previous studies, it was asked whether age and/or previous experience of childbirth pain had any influence on pain perception. The first study employed a within-subjects design of young university women in order to investigate the relationship of dysmenorrhea and menstrual cycle phase to pain threshold, tolerance, and subjective pain intensity ratings. The second study employed a between-subjects design of young university women as well, in order to replicate the menstrual phase effect obtained in the first study. The third study employed a between-subjects design of older women as it dealt with the relationships of age and/or the experience of childbirth pain to the same measures of pain perception. It also dealt with defining further characteristics of dysmenorrhea as occurring in an older group of women (over 30 yrs of age). Results from the first two studies indicated a significant increase in pain sensitivity, measured as pain threshold, from the follicular to the luteal phase of the cycle but no overall significant effects of dysmenorrhea on laboratory-induced pain. In the second study, there was a significant interaction between menstrual phase and dysmenorrhea with respect to subjective pain ratings. These results partially replicated previous findings in the literature while employing a clinically relevant method of pain induction. Results from the third study indicated that previous experience of childbirth pain, independent of age, is a significant factor in the perception of laboratory-induced pain. These latter results have never before been reported in the pain literature and thus deserve further investigation. Possible implications for an adaptation-levels model are discussed.