Localised assisted hatching effect in cryopreserved blastocyst transfers

Evaluate the clinical outcome in oocyte donation cycles of cryopreserved blastocysts which had previously undergone a localised assisted hatching process. The study took place at IVI Murcia Clinic between November 2009 and January 2012. To differentiate between the assisted hatching (AH) effect carried out at the level of the inner cell mass (ICM) and that which was carried out at the level of the trophectoderm—opposite the ICM (TRP) — 60 vitrified blastocyst cases included in an oocyte donation program on day five of the embryo development cycle—were randomly selected to undergo the different AH treatments. Vitrified-thawed blastocysts were randomly subjected to localised assisted hatching on the same day of the transfer using the laser ZP thinning technique and after their re–expansion had taken place. The clinical results were analysed statistically using the Fisher test (P<0.05) in order to observe significant differences between both groups.Results: Table 1Fisher test, P<0.05AH ICMAH TRPPn2931Age3738Transferred embryo average1.31.5Pregnancy rate60.7%41.9%0.75Implantation rate52.8%35.6%0.16Biochemical miscarriage5.6%23.5%0.38Clinical miscarriage10.7%25.8%0.24 Open table in a new tab The results appear to point towards a favourable trend in applying assisted hatching techniques at the level of the inner cell mass; this result would agree with the results obtained by other groups which also defend the role played by inner cell mass in the embryo hatching process.