title: Influence of estrogen levels on thermal perception, pain thresholds, and pain tolerance: studies on women undergoing in vitro fertilization.
abstract: We examined the relationship between estrogen and pain in women undergoing in vitro fertilization (IVF). Quantitative sensory tests (QST) were performed twice during the IVF-regimen: once during hormonal down-regulation and once during hormonal up-regulation. A group of healthy men and a group of women using monophasic contraceptives were also examined, to control for session-to-session effects. Among the women undergoing IVF, serum 17β-estradiol levels differed strongly between treatments as expected, and increased from 65.7 (SD = 26) pmol/L during the down-regulation phase, to 5,188 (SD = 2,524) pmol/L during the up-regulation phase. Significant outcomes in the QST were only seen for temperature perception thresholds (1.7 °C versus 2.2 °C; P = .003) and cold pain threshold (11.5 °C versus 14.5 °C; P = .04). A similar change in cold pain threshold was also seen in the 2 control groups, however, and statistical analysis suggested that this change was due to a session-to-session effect rather than being the result of hormonal modulation. Heat pain thresholds, heat tolerance, pressure pain thresholds, and the cold pressor test showed no significant differences between sessions. These data demonstrate that pain perception and pain thresholds in healthy women show little, if any, changes even with major variations in serum estradiol levels.
  
  
  CONCLUSIONS
  This study shows that pain perception and tolerance in women undergoing in vitro fertilization do not vary, despite the dramatic changes in 17β-estradiol levels induced by the treatment regimen. The result thus suggests that in humans, contrary to experimental animals, changes in estrogen levels have little influence on pain sensitivity.
authors.affiliation: Division of Cell Biology, Department of Experimental and Clinical Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
authors.forename: Kent D
authors.initials: KD
authors.lastname: Stening
authors.forename: Göran
authors.initials: G
authors.lastname: Berg
authors.forename: Mats
authors.initials: M
authors.lastname: Hammar
authors.forename: Helene
authors.initials: H
authors.lastname: Voster
authors.forename: Olle
authors.initials: O
authors.lastname: Eriksson
authors.forename: Asa
authors.initials: A
authors.lastname: Amandusson
authors.forename: Anders
authors.initials: A
authors.lastname: Blomqvist
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003080:Cold Temperature / Q000009:adverse effects; D015536:Down-Regulation; D004958:Estradiol / Q000097:blood*; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010146:Pain / Q000097:blood* / Q000209:etiology* / Q000523:psychology; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D012737:Sex Factors; D015854:Up-Regulation
chemical_list: D004958:Estradiol