3. Fertilization in the Laboratory
The oocytes obtained are taken to the IVF laboratory and are prepared to be inseminated. In parallel, the donor semen is prepared to improve and increase its fertilizing capacity. The insemination will be done selecting those sperm with the best morphology and mobility. Here according to each case, we can do a classic IVF (placing the ovules or oocytes on a plague and leaving them in contact with the sperm) or do an ICSI, that is, introducing a single sperm in each of the obtained ovules.
The fertilized oocytes are confirmed the next day. From that moment, the embryos are kept in the type of culture suitable for their development. The embryos can remain in culture for 3 to 6days and depending on when transferred at the cell or blastocyst stage.
If the embryos have a thick membrane, embryologists may recommend assisted hatching, that is, decrease the thickness of the membrane and thus facilitate the embryo’s exit from its outer shell and adhere to the lining of the uterus so that implantation can occur.