Single thawed embryo transfer after PGD does not affect pregn...( Amsterdam The Netherlands: Transferr...)

Amsterdam, The Netherlands: Transferring just one embryo at a time to a woman's womb after embryos have undergone preimplantation genetic diagnosis (PGD) and freezing at the blastocyst stage has become a real option after researchers achieved pregnancy rates that were as good as those for blastocysts that had not had a cell removed for PGD before freezing. Their results mean that it will be possible to reduce the number of multiple pregnancies after PGD and the consequent complications associated with these pregnancies.

The research was presented at the 25th annual meeting of the European Society of Human Reproduction and Embryology in Amsterdam and published online in Europe's leading reproductive medicine journal, Human Reproduction, simultaneously today (Tuesday).

Dr Yacoub Khalaf, director of the assisted conception unit at Guy's and St Thomas' Hospital, London (UK), told the conference: "To the best of our knowledge, our study is the first to provide reassurance that a strategy of elective single embryo transfer in good prognosis patients seeking PGD, backed by an efficient PGD cryopreservation service, can result in pregnancy rates that are comparable to those for non-biopsied embryos that are frozen as part of conventional fertility treatment. These results should empower fertility centres to include PGD cycles for inherited genetic disorders in their efforts to reduce the multiple pregnancy rates after various forms of assisted conception treatment. Given the increasing number of PGD cycles performed each year, the advantage of widespread application of this policy would be considerable."

Until now, fertility specialists have not applied a single embryo transfer policy to PGD for inherited genetic disorders because of concerns about how well biopsied embryos survive after freezing and thawing. "It was thought that the effect of the biopsy might reduce the embryos' tolerance to freezing. This concern was not based on any scient
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