title: Mechanism of action of the levonorgestrel-releasing intrauterine system in the treatment of heavy menstrual bleeding.
abstract: OBJECTIVE
  To assess the efficacy and adverse effects, and reveal the effective pathway of the levonorgestrel-releasing intrauterine system (LNG-IUS) in the treatment of heavy menstrual bleeding.
  
  
  METHODS
  In a prospective single-center study in Istanbul, Turkey, the LNG-IUS was inserted in 60 patients diagnosed with heavy menstrual bleeding between January 2008 and June 2010. Menstrual bleeding pattern, coagulation parameters, uterine arterial blood flow, endometrial thickness, and uterine and ovarian volumes were assessed pre-insertion, and at 6 and 12months.
  
  
  RESULTS
  Forty-nine women completed the study. When compared with pre-insertion values, the LNG-IUS led to improvements in hemoglobin and marked decreases in visual bleeding scores, endometrial thickness, and fibrinogen levels (P<0.001); platelet count, international normalized ratio, prothrombin time, activated partial thromboplastin time, and uterine volume also decreased (P<0.05). No significant change in ovarian volumes, or uterine artery resistive and pulsatility indices was observed at 6 or 12months compared with pre-insertion values.
  
  
  CONCLUSIONS
  The decline in menstrual blood loss among LNG-IUS users was associated with local progestogenic effects and aggravation of intrinsic and extrinsic coagulation pathways. Although the LNG-IUS is a highly effective method for treating heavy menstrual bleeding, care must be taken when a patient has thromboembolic risk factors.
authors.affiliation: Department of Obstetrics and Gynecology, Istanbul Training and Research Hospital, Istanbul, Turkey. Electronic address: cuzuncakmak@gmail.com.
authors.forename: Uzunçakmak
authors.initials: U
authors.lastname: Cihangir
authors.forename: Akbay
authors.initials: A
authors.lastname: Ebru
authors.forename: Ekin
authors.initials: E
authors.lastname: Murat
authors.forename: Yaşar
authors.initials: Y
authors.lastname: Levent
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000187:drug effects; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004717:Endometrium / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007436:Intrauterine Devices, Medicated / Q000009:adverse effects; D016912:Levonorgestrel / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D008595:Menorrhagia / Q000188:drug therapy*; D008875:Middle Aged; D010053:Ovary / Q000378:metabolism; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D014421:Turkey; D055988:Uterine Artery / Q000378:metabolism; D014599:Uterus / Q000378:metabolism
chemical_list: D003271:Contraceptive Agents, Female; D016912:Levonorgestrel
keywords: Coagulation; Doppler; Hypercoagulability; Intrauterine device; Levonorgestrel; Levonorgestrel-releasing intrauterine system; Thrombocytopenia; Uterine volume