title: Cannulation of a resistant internal os with the malleable outer sheath of a coaxial soft embryo transfer catheter does not affect in vitro fertilization-embryo transfer outcome.
abstract: OBJECTIVE
  To assess the impact of cannulation of a resistant cervical os with the outer malleable sheath of a double-lumen, soft ET catheter on IVF-ET outcomes.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  University-based IVF center.
  
  
  METHODS
  One hundred forty-two patients undergoing 142 ETs.
  
  
  METHODS
  Trial ultrasound-guided ET at all transfers, leaving the malleable outer sheath in situ when the soft inner catheter could not negotiate the internal os.
  
  
  METHODS
  Implantation rate and clinical pregnancy rate.
  
  
  RESULTS
  In 102 ETs (71.8%), the soft inner sheath easily negotiated the internal os (group 1). Forty ETs (28.2%) required cannulation of resistant internal ora with the outer sheath of the trial catheter (group 2). Implantation rates (35% vs. 32% in groups 1 and 2, respectively) and clinical pregnancy rates (50% vs. 45%) were not significantly different between groups. Blood was present on the transfer catheter after ET more frequently in group 2 than in group 1 (55% vs. 15%); however, neither the implantation rate nor the clinical pregnancy rate were affected by the presence of blood.
  
  
  CONCLUSIONS
  Cannulation of a resistant internal os by the malleable outer sheath and blood on the transfer catheter after ET do not have an adverse effect on implantation rate or clinical pregnancy rate.
authors.affiliation: Division of Biology and Medicine, Women and Infants' Hospital of Rhode Island, Brown Medical School, Providence 02905, USA.
authors.forename: Tali
authors.initials: T
authors.lastname: Silberstein
authors.forename: Sherry
authors.initials: S
authors.lastname: Weitzen
authors.forename: David
authors.initials: D
authors.lastname: Frankfurter
authors.forename: James R
authors.initials: JR
authors.lastname: Trimarchi
authors.forename: David L
authors.initials: DL
authors.lastname: Keefe
authors.forename: Shayne M
authors.initials: SM
authors.lastname: Plosker
mesh_terms: D001769:Blood; D002404:Catheterization / Q000009:adverse effects; D002584:Cervix Uteri; D015331:Cohort Studies; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D016017:Odds Ratio; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D016896:Treatment Outcome