Laser-assisted zona opening and trophectoderm biopsy at the blastocyst stage: a video guide

There are mainly two protocols to perform trophectoderm biopsy. The mostly used approach shows some intrinsic putative drawbacks due to the need for a zona pellucida drilling step at the cleavage stage. On the contrary, a more recent approach does not entail this step, since the opening of the zona pellucida and the retrieval of the biopsy fragment are conducted simultaneously. Indeed, the embryo may be left undisturbed up to the fully-expanded blastocyst stage without any potential perturbation to its development. This paper is a video guide to this latter biopsy protocol.