9. Blastocyst versus early cleavage embryo transfer: a retrospective analysis of 4,165 transfers.
A retrospective analysis of all the ovarian stimulation-in vitro fertilization-embryo transfer cycles was performed at the Centre for Human Reproduction, Athens, Greece, between June 1997 and December 2001 to compare the clinical outcomes after the transfer of blastocysts versus early cleavage embryos in assisted reproduction technologies (ART). The number of blastocysts transferred per ET was significantly lower compared to that of all early cleavage embryos. The implantation rate of blastocysts was significantly higher compared to that of all other modes of transfer. Clinical pregnancy rate after the transfer of blastocysts was significantly increased compared to that after transfer of any early cleavage embryo. The viable pregnancy rate after the transfer of blastocysts was significantly increased only compared to that after the transfer of day-2 embryos. There were no significant differences regarding the multiple gestation rates among the various modes of transfer.
CONCLUSION:The use of blastocysts in ART is beneficial when compared to that of day-2 embryos and at least comparable to that of day-3 embryos. Blastocyst culture and transfer remains a favourable and promising option in ART.
Reference
Pantos K, Makrakis E, Karantzis P, Stavrou D, Grammatis M, Chronopoulos K. Blastocyst versus early cleavage embryo transfer: a retrospective analysis of 4,165 transfers. Clin Exp Obstet Gynecol. 2004;31(1):42-4.
10. Single blastocyst transfer: a prospective randomized trial.
A prospective randomized trial was conducted in 48 women undergoing IVF-embryo transfer with day 3 FSH 12 mm in diameter on day of hCG administration in order to determine the efficacy of single blastocyst transfer. Embryo culture to the blastocyst stage was performed in sequential media G1/G2 followed by transfer of either one or two blastocysts. The transfer of a single blastocyst resulted in an implantation and ongoing pregnancy rate of 60.9% with no twins. The transfer of two blastocysts resulted in an implantation rate of 56%, an ongoing pregnancy rate of 76% with a 47.4% incidence of twins.
CONCLUSION(S): Single blastocyst transfer is an effective method of eliminating multiple births while maintaining high pregnancy rates in this selected group of patients.
Reference
Gardner DK, Surrey E, Minjarez D, Leitz A, Stevens J, Schoolcraft WB.
Single blastocyst transfer: a prospective randomized trial. Fertil Steril. 2004 Mar;81(3):551-5.
11. Blastocyst-stage embryo transfer in patients who failed to conceive in three or more day 2-3 embryo transfer cycles: a prospective, randomized study.
A prospective, randomized study was conducted to compare blastocyst-stage embryo transfers (ETs) with day 2-3 ETs in 54 patients with an adequate ovarian response who failed to conceive in three or more day 2-3 IVF/ET cycles. Ovarian down-regulation was obtained using GnRH agonist, and controlled ovarian hyperstimulation was achieved using daily administration of gonadotropins. The rate of blastocyst formation, ET cancellations, pregnancies, implantation, multiple gestation, and live births were determined. The clinical pregnancy rates per oocyte retrieval were 21.7% and 12.9% per blastocyst and day 2-3 ETs, respectively. Although there was a significantly higher implantation rate for blastocyst embryos (21.2%) as compared with 48- to 72-hour embryos (6%), the multiple-pregnancy rate was not significantly different between both groups. An ET cancellation rate of 26% and 6.4% for blastocyst and day 2-3 ETs, respectively, was observed. The presence of two or more 8-cell embryos on day 3 in culture carried a high probability of obtaining blastocysts for transfer.
CONCLUSION(S): This prospective randomized study suggests that in patients with an adequate ovarian response who failed to conceive in at least three IVF/ET cycles [1]. transfer of blastocyst-stage embryos carries a significantly higher implantation rate; [2]. the pregnancy rate per oocyte retrieval and ET are higher in the blastocyst-stage group, even if it did not reach statistical significance; [3]. a higher ET cancellation rate was observed in the whole blastocyst-stage group; [4]. the ET cancellation rate was reduced significantly if the decision to proceed to blastocyst transfer was made on day 3 after oocyte retrieval, which is a post hoc conclusion.
Reference
Blastocyst-stage embryo transfer in patients who failed to conceive in three or more day 2-3 embryo transfer cycles: a prospective, randomized study. Fertil Steril. 2004 Mar;81(3):567-71.