title: Psychophysically determined thresholds for thermal perception and pain perception in healthy women across the menstrual cycle.
abstract: OBJECTIVE
  Several studies have indicated changes in sensation and/or pain sensitivity among women across the menstrual cycle, but the pattern of the changes varies considerably. One reason for the reported discrepancies could reside in lack of biochemical definition of menstrual cycle phase. The aim was to quantify temperature and temperature pain thresholds at biochemically defined stages of the menstrual cycle.
  
  
  METHODS
  Nineteen healthy women were included in the study. Temperature and temperature pain thresholds were evaluated by quantitative sensory testing, performed at 3 occasions during the menstrual cycle (early follicular phase, late follicular phase, and mid-luteal phase). At each test session, serum concentrations of estradiol and progesterone were assessed.
  
  
  RESULTS
  Thermal cold perception threshold at the mammilla was significantly lower in the late follicular and mid-luteal phases, compared with the early follicular phase (P<0.05, respectively). For the remaining test sites, no cycle related differences in thermal perception or thermal thresholds could be documented.
  
  
  CONCLUSIONS
  The present study has indicated no major changes in thermal pain thresholds related to phase of the menstrual cycle for the tested locations, although thermal cold perception threshold at the mammilla was a significantly lower in the late follicular and mid-luteal phases, compared with the early follicular phase. The findings of the present study further underlines the need for strict criteria for menstrual cycle phase when studying pain sensitivity in relation to hormonal events in women.
authors.affiliation: Department of Pharmacology and Clinical Neurosciences, Clinical Neurophysiology, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Söderberg
authors.forename: Inger
authors.initials: I
authors.lastname: Sundström Poromaa
authors.forename: Sigrid
authors.initials: S
authors.lastname: Nyberg
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Bäckström
authors.forename: Erik
authors.initials: E
authors.lastname: Nordh
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000502:physiology* / Q000523:psychology; D017288:Pain Threshold / Q000502:physiology* / Q000523:psychology; D012016:Reference Values; D012684:Sensory Thresholds / Q000502:physiology; D013697:Thermosensing / Q000502:physiology*