title: Correlation between endometrial histology, microvascular density and calibre, matrix metalloproteinase-3 and bleeding pattern in women using a levonorgestrel-releasing intrauterine system.
abstract: BACKGROUND
  The main reason for discontinuation of the levonorgestrel-releasing intrauterine system (LNG-IUS) is unpredictable bleeding pattern.
  
  
  METHODS
  The objective of the study was to evaluate the endometrial histology, microvascular density and calibre, and the quantification of matrix metalloproteinase (MMP-3) in long-term users of LNG-IUS, with and without bleeding. Endometrial biopsies were obtained from 58 healthy women, 29 who maintained some degree of endometrial bleeding and 29 who were amenorrhoeic.
  
  
  RESULTS
  In the histological analysis, the majority of samples displayed a progestin-modified appearance. The major glandular diameter and the perimeter were significantly greater in the group of women with amenorrhoea. A significantly higher number of leukocytes was found in the group with bleeding (P = 0.014). No significant correlation was observed between the microvascular density or calibre and the bleeding pattern. MMP-3 showed a significantly higher number of reactive cells (P = 0.005) in the group who maintained some degree of bleeding.
  
  
  CONCLUSIONS
  Women using LNG-IUS who maintained endometrial bleeding during its use presented a higher number of leukocytes and MMP-3 in the endometrium when compared to women using LNG-IUS who became amenorrhoeic. However, the results did not provide evidence for microvascular pattern changes.
authors.affiliation: Human Reproduction Unit, Department of Obstetrics and Gynaecology, School of Medicine, Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil.
authors.forename: Marilia
authors.initials: M
authors.lastname: Oliveira-Ribeiro
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Petta
authors.forename: Liliana A L
authors.initials: LA
authors.lastname: De Angelo Andrade
authors.forename: Luis
authors.initials: L
authors.lastname: Bahamondes
authors.forename: Margarete M
authors.initials: MM
authors.lastname: Hidalgo
mesh_terms: D000328:Adult; D000568:Amenorrhea / Q000378:metabolism / Q000473:pathology*; D001706:Biopsy; D003271:Contraceptive Agents, Female / Q000008:administration & dosage / Q000009:adverse effects*; D004717:Endometrium / Q000098:blood supply / Q000201:enzymology / Q000473:pathology*; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000473:pathology; D016912:Levonorgestrel / Q000008:administration & dosage / Q000009:adverse effects*; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D008598:Menstruation / Q000187:drug effects*; D008833:Microcirculation / Q000187:drug effects / Q000473:pathology; D017154:Stromal Cells / Q000201:enzymology
chemical_list: D003271:Contraceptive Agents, Female; D016912:Levonorgestrel; D019278:Matrix Metalloproteinase 3