title: Middle to lower uterine segment embryo transfer improves implantation and pregnancy rates compared with fundal embryo transfer.
abstract: OBJECTIVE
  To assess differences in pregnancy and implantation rates as a function of the embryo placement.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  A tertiary care center.
  
  
  METHODS
  All fresh, nondonor IVF cycles performed in 2001.
  
  
  METHODS
  Alteration in embryo transfer (ET) target location from the fundal region to the middle to lower uterine segment.
  
  
  METHODS
  Clinical pregnancy rate (sonographic sac evidence/number of transfer cycles), implantation rate (number of sacs/number of embryos transferred), patient age, peak E(2), and fertilization rate.
  
  
  RESULTS
  A total of 393 fundal and 273 lower to middle uterine segment ETs were performed. The pregnancy (PR), implantation, and birth rates were significantly higher after a middle to lower uterine segment ET compared with fundal ET (39.6% vs. 31.2%; 21% vs. 14%; and 34.1% vs. 26.2%, respectively). Groups did not differ regarding patient age, basal FSH, peak E(2), number of intracytoplasmic sperm injection (ICSI) cycles, fertilization rate, embryo quality, or number of embryos transferred.
  
  
  CONCLUSIONS
  Both PR and implantation rates are favorably affected by directing embryo placement to the lower to middle uterine segment. By some unknown mechanism, it appears that this endometrial location provides a more favorable region for embryo deposition.
authors.affiliation: Women and Infants' Hospital of Rhode Island, Brown Medical School Division of Biology and Medicine, Providence, Rhode Island, USA. dfrankfurter@mfa.gwu.edu
authors.forename: David
authors.initials: D
authors.lastname: Frankfurter
authors.forename: James B
authors.initials: JB
authors.lastname: Trimarchi
authors.forename: Celso P
authors.initials: CP
authors.lastname: Silva
authors.forename: David L
authors.initials: DL
authors.lastname: Keefe
mesh_terms: D015331:Cohort Studies; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies