title: Interim analysis of a randomized clinical trial comparing abdominal versus transvaginal ultrasound-guided embryo transfer.
abstract: OBJECTIVE
  Ultrasound-guided embryo transfer appears to improve overall pregnancy outcomes for in vitro fertilization embryo transfer cycles. Most reports are done using a transabdominal ultrasound-guided approach, in contrast to a transvaginal ultrasound, which does not require a full bladder. We sought to determine if either approach was better with respect to clinical pregnancy outcomes.
  
  
  METHODS
  This randomized clinical trial took place in a university-based practice with an enrollment of 186 subjects. Secondary measures also included embryo transfer time and degree of cramping and pain, which subjects ranked as none = 1; mild = 2; moderate = 3; or severe = 4.
  
  
  RESULTS
  There were no differences in implantation rates (33.1 + or - 4.1%, + or - standard error vs 31.1 + or - 3.9%, P = 0.78), pregnancy rates (60% vs 54%, P = 0.38), clinical pregnancy rates (48% vs 45%, P = 0.77), and live-birth rates (30% vs 39%, P = 0.37) between transabdominal and transvaginal ultrasound-guided embryo transfer groups. No differences were noted between groups for time required for embryo transfer (157 + or - 279 seconds vs 130 + or - 176 seconds, P = 0.92), uterine cramping (1.2 + or - 0.5 vs 1.2 + or - 0.4, P = 0.4), and the degree of pain (1.4 + or - 0.7 vs 1.3 + or - 0.5, P = 0.13).
  
  
  CONCLUSIONS
  Neither transabdominal nor transvaginal ultrasound-guided embryo transfer is more beneficial in optimizing pregnancy outcomes. While delays often occur while waiting for bladder distension for transabdominal ultrasound-guided embryo transfer, uterine position, parity and level of physician comfort should dictate the choice of either approach.
authors.affiliation: Obstetrics and Gynecology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA.
authors.forename: Natalie
authors.initials: N
authors.lastname: Porat
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Boehnlein
authors.forename: Calisa M
authors.initials: CM
authors.lastname: Schouweiler
authors.forename: Jungae
authors.initials: J
authors.lastname: Kang
authors.forename: Steven R
authors.initials: SR
authors.lastname: Lindheim
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging*; D016009:Chi-Square Distribution; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D016896:Treatment Outcome; D014463:Ultrasonography / Q000379:methods*; D014599:Uterus / Q000000981:diagnostic imaging*; D014621:Vagina / Q000000981:diagnostic imaging*