title: The effect of oral contraceptives on uterine contractility and menstrual pain: an assessment with cine MR imaging.
abstract: BACKGROUND
  Low-dose oral contraceptives (OC) have been reported to control primary dysmenorrhea. Furthermore, a close relationship between dysmenorrhea and uterine contractions has been visualized with magnetic resonance imaging (MRI). This study aimed to use cine MR to demonstrate the effects of OC on myometrial contractility during menstruation and to associate the findings with dysmenorrhea.
  
  
  METHODS
  MR studies were obtained of 21 healthy female volunteers (22-47 years old) taking OC, and 20 control women (24-39 years old) not taking OC. Cine- and static MR images were obtained with a 1.5 T magnet during menstruation. Uterine contractility was assessed by the presence of endometrial distortion on cine MR, the area of the mid-sagittal uterine myometrium, and the thickness of the subendometrial low-intensity area on static images. Dysmenorrhea were assessed via a questionnaire.
  
  
  RESULTS
  A total of 21 OC users and 20 controls were included in the analysis. Endometrial distortion was significantly less prominent and the subendometrial low-intensity area was significantly thinner in the OC group. Furthermore in the OC group, the uterine myometrial area was larger (although not significantly) and the degree of assessed pain was significantly lower.
  
  
  CONCLUSIONS
  Both cine- and static MR images demonstrate that myometrial contractility was relatively suppressed in OC users, which may represent one of the reasons explaining the reduced menstrual pain experienced by OC users.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan. akikido@kuhp.kyoto-u.ac.jp
authors.forename: Aki
authors.initials: A
authors.lastname: Kido
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
authors.forename: Masako
authors.initials: M
authors.lastname: Kataoka
authors.forename: Yoji
authors.initials: Y
authors.lastname: Maetani
authors.forename: Asako
authors.initials: A
authors.lastname: Nakai
authors.forename: Milliam L
authors.initials: ML
authors.lastname: Kataoka
authors.forename: Takashi
authors.initials: T
authors.lastname: Koyama
authors.forename: Shingo
authors.initials: S
authors.lastname: Fujii
mesh_terms: D000328:Adult; D003276:Contraceptives, Oral / Q000008:administration & dosage*; D004412:Dysmenorrhea / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008597:Menstrual Cycle; D008875:Middle Aged; D015233:Models, Statistical; D014590:Uterine Contraction / Q000187:drug effects*; D014599:Uterus / Q000473:pathology
chemical_list: D003276:Contraceptives, Oral