[Blastocyst quality criteria].
Embryo culture to the blastocyst stage has progressed enormously with the new generation of acellular culture media, or sequential media. The main advantages of embryo transfer at the blastocyst stage are that it provides a natural embryo selection during culture, or a selection using preimplantation diagnosis, it provides better conditions for SET, avoiding multiple pregnancies and overcoming repeated IVF failures by improving embryo selection. The risks are failing to select a single blastocyst or obtaining a limited number of frozen blastocysts, with reduced survival after thawing. However, prolonged embryo culture seems to be good practice for day 3 embryos with delayed development, and blastocyst transfer. More effective at day 5 than at day 6.
Nogueira
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Laboratoire de Biologie de la Reproduction-IFREARES, 20 route de Ravel, Toulouse, France. daniela_nogueira@yahoo.com
D001755:Blastocyst / Q000502:physiology*; D002470:Cell Survival; D004624:Embryo Transfer; D006801:Humans; D008423:Maternal Age