title: Anatomical causes of difficult embryo transfer during in vitro fertilization.
abstract: OBJECTIVE
  Identify, define and validate through statistical analysis the anatomical causes of difficult embryo transfers (ET).
  
  
  METHODS
  This observational study, carried out in 306 IVF candidates, compared the frequency of anatomical anomalies of the uterus and cervix in women who underwent an easy ET with that in women who underwent a difficult ET. Anatomical anomalies were detected during an assessment of the cervix and uterus including transvaginal ultrasound, hysteroscopy and a mock transfer. Ease of ET was determined during the actual transfer procedure.
  
  
  RESULTS
  An easy ET was achieved in 151 patients, whereas difficulties occurred in 155 patients, among whom 55 patients underwent a "very difficult" ET. The most common anatomical characteristics associated with difficult ET were abnormal crypts in the cervical canal (86%) and tortuosity of the cervical canal (68%). Less frequent causes included: internal os contractions (28%) and pronounced anteversion of the uterus (26%). Very difficult ETs were associated with the presence of several causes.
  
  
  CONCLUSIONS
  ET is the clinical step that has the most effect on IVF outcome. Difficult transfers are associated with a fall in pregnancy rates. The anatomical causes of difficult transfer identified in this study led to major changes in transfer procedure in our department and to the development of more adapted catheters.
authors.affiliation: Centre de fertilité, groupe hospitalier Diaconesses-Croix-St-Simon, 18, rue du Sergent-Bauchat, 75012 Paris, France. Electronic address: llarue@hopital-dcss.org.
authors.forename: L
authors.initials: L
authors.lastname: Larue
authors.affiliation: Centre de fertilité, groupe hospitalier Diaconesses-Croix-St-Simon, 18, rue du Sergent-Bauchat, 75012 Paris, France.
authors.forename: G
authors.initials: G
authors.lastname: Keromnes
authors.affiliation: Centre de fertilité, groupe hospitalier Diaconesses-Croix-St-Simon, 18, rue du Sergent-Bauchat, 75012 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Massari
authors.affiliation: Centre de fertilité, groupe hospitalier Diaconesses-Croix-St-Simon, 18, rue du Sergent-Bauchat, 75012 Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Roche
authors.affiliation: Laboratoire Drouot, 19, rue Drouot, 75009 Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Bouret
authors.affiliation: Laboratoire Drouot, 19, rue Drouot, 75009 Paris, France.
authors.forename: N G
authors.initials: NG
authors.lastname: Cassuto
authors.affiliation: Centre de fertilité, groupe hospitalier Diaconesses-Croix-St-Simon, 18, rue du Sergent-Bauchat, 75012 Paris, France.
authors.forename: J P
authors.initials: JP
authors.lastname: Ayel
mesh_terms: D000328:Adult; D002584:Cervix Uteri / Q000002:abnormalities* / Q000000981:diagnostic imaging; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D015907:Hysteroscopy; D011247:Pregnancy; D018873:Pregnancy Rate; D014599:Uterus / Q000002:abnormalities* / Q000000981:diagnostic imaging
keywords: Bilan cervico-utérin; Difficult transfer; Embryo transfer; Fécondation in vitro; In vitro fertilization; Personalized healthcare; Soins personnalisés; Transfert difficile; Transfert d’embryons; Uterocervical assessment