title: A Wallace malleable stylet for difficult embryo transfer in an in vitro fertilization program: a case-control study.
abstract: BACKGROUND
  The aim of the study was to evaluate the impact of using a Wallace malleable stylet in combination with an Edwards-Wallace embryo replacement catheter in case of difficult embryo transfer (ET).
  
  
  METHODS
  A retrospective case-control study was used. The standard ET procedure at the clinic was to use a single tooth tenaculum, and a speculum to straighten the cervical canal prior to inserting the Edwards-Wallace embryo replacement catheter. In 205 of 2041 (10%) fresh ET difficulties were experienced during ET and a Wallace malleable stylet was used to place the outer catheter sheath correctly. This stylet transfer group was compared with a control transfer group of 410 ET performed just before and after each stylet transfer.
  
  
  RESULTS
  No differences in number of transferred embryos, cleavage stage, or embryo morphology score were found between the two groups. We found no differences in implantation rates (20.7 and 19.2% [95% confidence interval (CI) 0.8-1.5]) or delivery rates (29.3 and 25.4% [CI 0.8-1.8]) between the study and control group.
  
  
  CONCLUSIONS
  Using a Wallace malleable stylet in combination with an Edwards-Wallace embryo replacement catheter in case of difficult ET has no negative impact on implantation and delivery rates.
authors.affiliation: The Fertility Clinic, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, Copenhagen, Denmark.
authors.forename: Ingrid Kirstine
authors.initials: IK
authors.lastname: Nielsen
authors.forename: Anette
authors.initials: A
authors.lastname: Lindhard
authors.forename: Anne
authors.initials: A
authors.lastname: Loft
authors.forename: Søren
authors.initials: S
authors.lastname: Ziebe
authors.forename: Anders Nyboe
authors.initials: AN
authors.lastname: Andersen
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002404:Catheterization; D016009:Chi-Square Distribution; D003718:Denmark; D004624:Embryo Transfer / Q000295:instrumentation*; D005260:Female; D005307:Fertilization in Vitro / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D011247:Pregnancy / Q000706:statistics & numerical data*; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity