title: Characterizing ectopic pregnancies that rupture despite treatment with methotrexate.
abstract: OBJECTIVE
  To identify risk factors for tubal rupture among ectopic pregnancies treated with methotrexate (MTX).
  
  
  METHODS
  Retrospective case-control analysis.
  
  
  METHODS
  An urban medical center.
  
  
  METHODS
  Eighty-one women diagnosed with an ectopic gestation treated with MTX: 19 patients experienced subsequent tubal rupture, and 62 patients experienced ectopic resolution.
  
  
  METHODS
  None.
  
  
  METHODS
  Predictive variables including serial human chorionic gonadotropin (hCG) values.
  
  
  RESULTS
  The hCG incremental rate before as well as after MTX administration was positively associated with tubal rupture. HCG values prior to ectopic diagnosis that increased at least 66% over 48 hours and rising hCG values after treatment with methotrexate were independent predictors of tubal rupture. A disproportionate number (47%) of ectopic pregnancies that ruptured were located in the tubal isthmus.
  
  
  CONCLUSIONS
  The hCG incremental rate both before and after MTX represents an independent risk factor for subsequent tubal rupture. Concentrations of hCG before ectopic diagnosis that increased at least 66% over 48 hours, or persistently rising hCG concentrations after treatment with MTX, may lower the threshold for surgical intervention. Implantation site may represent an unidentifiable risk factor for tubal rupture.
authors.affiliation: Department of Obstetrics and Gynecology, Baylor College of Medicine, Texas Medical Center, Houston, Texas 77030, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Dudley
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Heard
authors.forename: Haleh
authors.initials: H
authors.lastname: Sangi-Haghpeykar
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Carson
authors.forename: John E
authors.initials: JE
authors.lastname: Buster
mesh_terms: D000020:Abortifacient Agents, Nonsteroidal / Q000627:therapeutic use*; D016022:Case-Control Studies; D006063:Chorionic Gonadotropin / Q000097:blood; D005184:Fallopian Tube Diseases / Q000209:etiology*; D005260:Female; D006801:Humans; D008727:Methotrexate / Q000627:therapeutic use*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000097:blood / Q000150:complications* / Q000188:drug therapy*; D012189:Retrospective Studies; D012307:Risk Factors; D012422:Rupture, Spontaneous
chemical_list: D000020:Abortifacient Agents, Nonsteroidal; D006063:Chorionic Gonadotropin; D008727:Methotrexate