A prospective randomized multicenter study to evaluate the best day for embryo transfer: does the outcome justify prolonged embryo culture?
OBJECTIVE
This study aimed to evaluate the best day for embryo transfer in a prospective unrestricted randomized multicenter trial.


METHODS
Data were collected on a preformed Excel-sheet which contained random numbers from 1 to 5 for each subsequent patient as a preprogrammed day for embryo transfer. Information was requested on patient's age, indication for sterility treatment, stimulation protocol used, numbers of oocytes retrieved, fertilized oocytes, cryopreserved embryos, and cell stage of embryos transferred.


RESULTS
A total of 329 embryo transfers were performed, resulting in 106 clinical pregnancies (32.2%). Pregnancy rates achieved were 20.0% on day 1, 30.4% on days 2 and 3, and 50.0% on days 4 and 5 (p = 0.03).


CONCLUSIONS
Within the scope of the present randomized multicenter trial, embryo transfers performed on days 4 and 5 enhanced the pregnancy rate significantly, compared to those of days 1, 2, and 3.
Margreiter
Markus
M
'Wunschbabyzentrum"--Institute for Sterility Treatment, Vienna, Austria.
Weghofer
Andrea
A
Kogosowski
Avi
A
Mahmoud
Kamal Zak
KZ
Feichtinger
Wilfried
W
D000328:Adult; D001755:Blastocyst / Q000502:physiology; D004624:Embryo Transfer / Q000592:standards*; D005314:Embryonic and Fetal Development / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D013997:Time Factors