title: Ultrasound guided embryo transfer significantly improves pregnancy rates in women undergoing oocyte donation.
abstract: OBJECTIVE
  Recent reports suggest ultrasound (US) guided embryo transfer (ET) improves pregnancy rates. Using the ovum donation model to eliminate confounding variables, we assessed the impact of US guided ET on pregnancy rates, implantation rates, and multiple gestation rates.
  
  
  METHODS
  All women who underwent IVF-ET cycles using donated oocytes from November 1997 to September 1998 (n = 137) were evaluated retrospectively. ET from November 1997 to April 1998 were performed without US, while all ET from May 1998 to September 1998 were performed using transvaginal or transabdominal US. ET was further categorized as easy or difficult. Difficult ET was defined as requiring at least two attempts and/or the presence of blood on the catheter and/or > 5 min.
  
  
  RESULTS
  Pregnant patients (n = 73) were similar with respect to the number and morphology of the embryos transferred compared to non-pregnant patients (n = 65). US guidance significantly improved implantation and pregnancy rates in cycles with easy transfers [28.8 vs. 18.4% and 63.1 vs. 36.1%, respectively (P < 0.05)] without impacting multiple pregnancy rates.
  
  
  CONCLUSIONS
  US guided ET is simple and reassuring and appears to significantly improve pregnancy outcomes in ovum donation cycles by optimizing the placement of embryos.
authors.affiliation: Department of Obstetrics and Gynecology, Columbia University, New York, NY, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Lindheim
authors.forename: M A
authors.initials: MA
authors.lastname: Cohen
authors.forename: M V
authors.initials: MV
authors.lastname: Sauer
mesh_terms: D000328:Adult; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D018587:Oocyte Donation; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D018084:Ultrasonography, Interventional