title: Cyclooxygenase-2 expression in the endometrium and its relationship to bleeding in users of continuous oral contraceptives.
abstract: OBJECTIVE
  The objective of the present study was to investigate whether or not the presence of irregular bleeding during use of oral contraceptives (OC) is associated with increased cyclooxygenase-2 (COX-2) expression.
  
  
  METHODS
  An observational study was carried out in 26 patients who were using gestodene 75 microg/ethinylestradiol 30 microg prior to endometrial resection. The patients were divided into two groups: those with amenorrhea (n = 14) and those who had irregular bleeding (n = 12). The resected endometrium was immunostained for COX-2, Bcl-2 and Ki-67 expression. Routine pathology was carried out using standard hematoxylin-eosin staining.
  
  
  RESULTS
  Irregular bleeding during OC use was associated with strong COX-2 expression in both glandular and superficial epithelium. There were also more patients in this group with irregular endometrial maturation and higher Ki-67 values. Bcl-2 expression, on the other hand, was not affected by the presence of uterine bleeding.
  
  
  CONCLUSIONS
  The presence of irregular bleeding during OC use is associated with strong COX-2 expression in the endometrium, thereby suggesting a pivotal role of prostaglandins in this process.
authors.affiliation: Centro de Pesquisa e Assistência em Reprodução Humana (CEPARH), Salvador, Bahia, Brazil. ceparh@uol.com.br
authors.forename: Hugo
authors.initials: H
authors.lastname: Maia
authors.forename: Tânia
authors.initials: T
authors.lastname: Correia
authors.forename: Luis
authors.initials: L
authors.lastname: Freitas
authors.forename: Célia
authors.initials: C
authors.lastname: Athayde
authors.forename: Elsimar M
authors.initials: EM
authors.lastname: Coutinho
mesh_terms: D000328:Adult; D003276:Contraceptives, Oral / Q000009:adverse effects*; D051546:Cyclooxygenase 2 / Q000032:analysis*; D004717:Endometrium / Q000201:enzymology*; D004848:Epithelium / Q000201:enzymology; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D014592:Uterine Hemorrhage / Q000139:chemically induced / Q000201:enzymology*
chemical_list: D003276:Contraceptives, Oral; D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D051546:Cyclooxygenase 2