title: Day 3 versus day 5 embryo transfer: a prospective randomized study.
abstract: Transfer of embryos at the blastocyst stage has been associated with exceptionally high implantation rates. There are, however, only a few prospective randomized studies comparing day 3 versus day 5 embryo transfer. Furthermore, the number of embryos replaced in the day 3 group transfer is often higher than the number of blastocysts replaced, thereby affecting implantation rates. A total of 118 patients undergoing standard IVF/intracytoplasmic sperm injection who had developed at least three 8-cell embryos showing <20% extracellular fragmentation on day 3 were randomized for day 3 or day 5 transfer. A maximum of two embryos were replaced. In this prospective, randomized study the implantation and pregnancy potential of embryos transferred on day 3 or day 5 were compared. Equal numbers of embryos were replaced in the two groups. There was no statistically significant difference between day 3 and day 5 transfer regarding positive human chorionic gonadotrophin rates (70 versus 67%), clinical pregnancy rates (61 versus 51%), implantation rates (44 versus 37%), twinning rates (42 versus 41%) and rates of early pregnancy loss (15 versus 29%). Transfer of embryos on day 3 or 5 showed similar implantation rates when equal numbers of embryos were transferred. Embryo transfer at the blastocyst stage seems to have no advantage over day 3 transfer in patients with more than two 8-cell embryos showing less than 20% fragmentation on day 3.
authors.affiliation: Fertility Clinic, Skive Hospital, Skive, Denmark. mona.bungum@sygehusviborg.dk
authors.forename: M
authors.initials: M
authors.lastname: Bungum
authors.forename: L
authors.initials: L
authors.lastname: Bungum
authors.forename: P
authors.initials: P
authors.lastname: Humaidan
authors.forename: C
authors.initials: C
authors.lastname: Yding Andersen
mesh_terms: D001755:Blastocyst / Q000378:metabolism; D002478:Cells, Cultured; D015925:Cryopreservation; D003470:Culture Media / Q000494:pharmacology; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D007315:Insemination, Artificial; D008183:Luteal Phase; D008297:Male; D009865:Oocytes / Q000166:cytology; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D013094:Spermatozoa / Q000648:ultrastructure; D013997:Time Factors
chemical_list: D003470:Culture Media