Transfer Strategy in an Oocyte Donation Programme

Pilot Study of the Best Transfer Strategy in an Oocyte Donation Programme: an Intention to Treat Randomized Controlled Trial

It has been previously shown that although the activation of the embryonic genome can begin as early as two days of initiation of the embryonic development (D2), it is expressed on day 3 (D3). Without this activation, the embryo can not continue its development. Therefore, it has been suggested that extended culture to blastocyst stage could be an option to identify and better select embryos that have been able to carry out this activation. The purpose of this study is to compare cumulative pregnancy and live birth rates following transfer of cleavage embryos or blastocysts.

Inclusion Criteria:

• Patients under their first or second cycle of a synchronous (fresh) oocyte donation cycle.

Exclusion Criteria:

• Preimplantation genetic screening or diagnosis cycles.
• Patients with strict blastocyst-stage embryo transfer indication by the couple's treating physician.