Zygote versus embryo transfer: a prospective randomized multicenter trial.
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.
Dale
Brian
B
Center for Reproductive Biology, Clinica Villa Del Sole, Naples, Italy.
Fiorentino
Agnese
A
de Simone
Maria Laura
ML
di Matteo
Loredana
L
di Frega
Antonio Scotto
AS
Wilding
Martin
M
Fehr
Peter
P
Bassan
Emma
E
Lo Giudice
Cristoforo
C
Maselli
Antonio
A
Cappiello
Fulvio
F
Zullo
Fulvio
F
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