title: Use of the etonogestrel-releasing implant is associated with hypoactivation of the coagulation cascade.
abstract: BACKGROUND
  The role of progestogens in haemostasis is controversial. Our objective is to evaluate the haemostatic effects of an etonogestrel-releasing implant.
  
  
  METHODS
  This open-label, self-controlled, longitudinal study involved 20 healthy women receiving subcutaneous etonogestrel-releasing implants. At baseline, 1, 3 and 6 months, we measured the following: activated partial thromboplastin time; prothrombin time; thrombin time; fibrinogen; coagulation factors II, V, VII, VIII, IX, X and XI; von Willebrand factor; activated protein C (APC); antithrombin; free protein S; plasminogen activator inhibitor type 1 (PAI-1); alpha2-antiplasmin; thrombin-antithrombin (TAT) complex; prothrombin fragment 1 + 2 (F1 + 2); D-dimers; APC resistance. Statistical analyses included the Friedman test and ANOVA.
  
  
  RESULTS
  Levels of APC (P < 0.01), factor II (P = 0.02), factor VII (P = 0.006), factor X (P = 0.01) and F1 + 2 (P < 0.001) were reduced, whereas those of PAI-1 (P = 0.01) and factor XI (P = 0.006) were transitory increased. All of these values, however, remained within normal ranges. Surprisingly, TAT concentrations fell below the normal range (P < 0.001).
  
  
  CONCLUSIONS
  Our findings suggest that the etonogestrel-releasing implant does not induce a prothrombotic pattern during the first six months of use, and that its use is associated with a reduction in thrombin generation.
authors.affiliation: Department of Gynaecology and Obstetrics, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil. carol.sales@uol.com.br
authors.forename: C S
authors.initials: CS
authors.lastname: Vieira
authors.forename: R A
authors.initials: RA
authors.lastname: Ferriani
authors.forename: A A
authors.initials: AA
authors.lastname: Garcia
authors.forename: M C
authors.initials: MC
authors.lastname: Pintão
authors.forename: G D
authors.initials: GD
authors.lastname: Azevedo
authors.forename: M K O
authors.initials: MK
authors.lastname: Gomes
authors.forename: M F
authors.initials: MF
authors.lastname: Silva-de-Sá
mesh_terms: D000328:Adult; D000991:Antithrombins / Q000378:metabolism; D001777:Blood Coagulation / Q000187:drug effects*; D017135:Desogestrel / Q000008:administration & dosage* / Q000494:pharmacology; D004343:Drug Implants; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D006801:Humans; D011446:Prospective Studies; D011486:Protein C / Q000378:metabolism; D017293:Protein S / Q000378:metabolism; D013923:Thromboembolism / Q000517:prevention & control; D020246:Venous Thrombosis / Q000517:prevention & control; D000979:alpha-2-Antiplasmin / Q000378:metabolism
chemical_list: D000991:Antithrombins; D004343:Drug Implants; D005338:Fibrin Fibrinogen Degradation Products; D011486:Protein C; D017293:Protein S; D000979:alpha-2-Antiplasmin; C036309:fibrin fragment D; C044815:etonogestrel; D017135:Desogestrel