title: The local progestational effect of the levonorgestrel-releasing intrauterine system: a sonographic and Doppler flow study.
abstract: BACKGROUND
  We aimed to evaluate the effect of the levonorgestrel-releasing intrauterine system (LNG-IUS) on the uterine vasculature and the endometrium.
  
  
  METHODS
  The study was a prospective controlled study evaluating the local effects of LNG-IUS compared with the copper intrauterine device (IUD). Forty-seven women carrying LNG-IUS (group A) were compared with 35 women carrying copper IUD in a control group (group B). Clinical measures of menstrual bleeding, endometrial thickness and Doppler flow of the cervical branch of the uterine artery and spiral artery were evaluated and compared between the two groups.
  
  
  RESULTS
  Doppler flow in the cervical branch of the uterine artery did not reveal any changes between the groups (resistance index = 0.6 +/- 0.01 in both groups). Endometrial width was significantly thinner in group A (4.1 +/- 0.2 mm) compared with group B (7.3 +/- 0.2 mm) (P < 0.0001). Subendometrial flow in the spiral artery was significantly reduced in 35 women of group A (75%) and in none of group B (P < 0.0001).
  
  
  CONCLUSIONS
  The present study offers an explanation for the oligomenorrhoea in LNG-IUS users, i.e. a local progestational effect on the endometrium with no change in the blood flow in the uterine artery. This should be presented to the women in the pre-contraceptive counselling in order to lessen the discontinuation rate.
authors.affiliation: Department of Obstetrics and Gynecology, the Chaim Sheba Medical Center, (affiliated to the Sackler Faculty of Medicine, Tel-Aviv University), Tel-Hashomer, Israel. zale_y@netvision.net.il
authors.forename: Y
authors.initials: Y
authors.lastname: Zalel
authors.forename: A
authors.initials: A
authors.lastname: Shulman
authors.forename: A
authors.initials: A
authors.lastname: Lidor
authors.forename: R
authors.initials: R
authors.lastname: Achiron
authors.forename: S
authors.initials: S
authors.lastname: Mashiach
authors.forename: R
authors.initials: R
authors.lastname: Gamzu
mesh_terms: D000328:Adult; D001158:Arteries; D003271:Contraceptive Agents, Female / Q000008:administration & dosage*; D004717:Endometrium / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007435:Intrauterine Devices, Copper; D007436:Intrauterine Devices, Medicated / Q000009:adverse effects; D016912:Levonorgestrel / Q000008:administration & dosage*; D008875:Middle Aged; D009839:Oligomenorrhea / Q000209:etiology; D011446:Prospective Studies; D012039:Regional Blood Flow; D012212:Rheology; D014463:Ultrasonography; D014599:Uterus / Q000098:blood supply* / Q000000981:diagnostic imaging
chemical_list: D003271:Contraceptive Agents, Female; D016912:Levonorgestrel