title: Zygote versus embryo transfer: a prospective randomized multicenter trial.
abstract: OBJECTIVE
  To determine the efficiency of transferring human zygotes as opposed to human day 2 or 3 embryos.
  
  
  METHODS
  A prospective, randomized, Multicenter trial. Patients were randomized into zygote or embryo transfer. Patients were prepared for oocyte retrieval using standardized protocols. Oocyte retrieval was performed under general anesthesia. Oocytes and spermatozoa were treated using standard laboratory techniques. All protocols were coordinated by the coordinating center.
  
  
  RESULTS
  A total of 386 patients were included in the trial. Pregnancy rates were 36.5% after zygote transfer and 42% after embryo transfer. Implantation rates were equivalent (17%) in both groups.
  
  
  CONCLUSIONS
  No general difference was observed for zygote or embryo transfer. The results suggest that zygote transfer is a valid alternative to embryo transfer.
authors.affiliation: Center for Reproductive Biology, Clinica Villa Del Sole, Naples, Italy.
authors.forename: Brian
authors.initials: B
authors.lastname: Dale
authors.forename: Agnese
authors.initials: A
authors.lastname: Fiorentino
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: de Simone
authors.forename: Loredana
authors.initials: L
authors.lastname: di Matteo
authors.forename: Antonio Scotto
authors.initials: AS
authors.lastname: di Frega
authors.forename: Martin
authors.initials: M
authors.lastname: Wilding
authors.forename: Peter
authors.initials: P
authors.lastname: Fehr
authors.forename: Emma
authors.initials: E
authors.lastname: Bassan
authors.forename: Cristoforo
authors.initials: C
authors.lastname: Lo Giudice
authors.forename: Antonio
authors.initials: A
authors.lastname: Maselli
authors.forename: Fulvio
authors.initials: F
authors.lastname: Cappiello
authors.forename: Fulvio
authors.initials: F
authors.lastname: Zullo
mesh_terms: D000328:Adult; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000628:therapy; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D017388:Zygote Intrafallopian Transfer