Diagnostic efficiency and accuracy, embryonic development and clinical outcome after the biopsy of one or two blastomeres for preimplantation genetic diagnosis.

Preimplantation genetic diagnosis (PGD) can be considered as an alternative to prenatal diagnosis which circumvents the problem of therapeutic abortion for a genetic disease. It involves the genetic testing of blastomeres from preimplantation embryos followed by the selective transfer of embryos shown to be unaffected for the disease under study. The final goal of PGD is the birth of one healthy child and since genetic analysis is performed on one or two single blastomeres, it has to meet high standards of efficiency and accuracy. Important questions that arise are first whether the embryo development would significantly differ after the removal of only one cell as compared to two cells and secondly whether we can achieve the same level of diagnostic accuracy after the biopsy of one cell as compared to two-cell biopsy.
In order to answer these questions we enrolled patients with embryo biopsy in view of PGD or PGS in a randomized controlled trial (RCT) and assessed the diagnostic efficiency and accuracy as well as further embryonic development and clinical outcome after the removal of one or two blastomeres.

Removal of one cell from a preimplantation embryo in view of preimplantation genetic diagnosis is less detrimental than two cell removal and will lead to a higher number of ongoing pregnancies and births.

N/A

Embryos were obtained from patients undergoing PGD. One or two cells were removed from embryos with more than 6 cells at day 3. Embryos shown to be free of disease were replaced in the uterus. Some surplus embryos were re-analysed to measure accuracy.