title: The use of transvaginal color flow imaging after in vitro fertilization to identify optimum uterine conditions before embryo transfer.
abstract: OBJECTIVE
  To assess whether a measure of uterine blood flow impedance (the pulsatility index, PI) as determined by transvaginal ultrasonography with color blood flow imaging, may be used to assess endometrial receptivity immediately before the time of embryo transfer (ET) after assisted conception.
  
  
  METHODS
  A prospective study of infertile women who had undergone treatment to induce multiple follicular development followed by ultrasound-guided oocyte retrieval. The oocytes were fertilized in vitro.
  
  
  METHODS
  The Hallam Medical Centre.
  
  
  METHODS
  Eight-two women (22 to 44 years of age) who all had three or four good quality embryos available for transfer to the uterus.
  
  
  METHODS
  All women were examined by transvaginal ultrasonography, with color flow imaging and blood flow analysis, immediately before ET.
  
  
  METHODS
  The mean PI of the left and right uterine arteries, the pregnancy rate (PR) (%), the embryo implantation rate (%), and the multiple PR (%).
  
  
  RESULTS
  The patients were grouped according to whether the PI was low (1.00 to 1.99), medium (2.00 to 2.99), or high (3+). There were 27 women in the low PI group, 36 in the medium, and 19 in the high. The PR (%), embryo implantation rate (%), and multiple PR (%) were 41%, 15.3%, and 27.3% for the low PI group and 47%, 22.2%, and 47.1% for the medium PI group. There were no pregnancies in the high PI group. Thus 35% (19/54) of women who failed to become pregnant had a PI value greater than 3.0.
  
  
  CONCLUSIONS
  These data suggest that the PI value on the day of ET could be used to: (1) increase the implantation rate by showing which embryos should be cryopreserved until the uterus is more receptive and (2) reduce the multiple PR by indicating that the number of embryos transferred should be limited when the uterus is most receptive.
authors.affiliation: Department of Obstetrics and Gynaecology, King's College School of Medicine and Dentistry, London, United Kingdom.
authors.forename: C V
authors.initials: CV
authors.lastname: Steer
authors.forename: S
authors.initials: S
authors.lastname: Campbell
authors.forename: S L
authors.initials: SL
authors.lastname: Tan
authors.forename: T
authors.initials: T
authors.lastname: Crayford
authors.forename: C
authors.initials: C
authors.lastname: Mills
authors.forename: B A
authors.initials: BA
authors.lastname: Mason
authors.forename: W P
authors.initials: WP
authors.lastname: Collins
mesh_terms: D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008954:Models, Biological; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012039:Regional Blood Flow; D014463:Ultrasonography / Q000379:methods*; D014599:Uterus / Q000098:blood supply* / Q000000981:diagnostic imaging; D014621:Vagina