Every embryo has its moment
Long culture to blastocyst involves leaving the embryo until day 5 (or, sometimes, day 6). This helps us to better select the embryos with the highest chances of implantation.
With this technique we increase our pregnancy rates, although not all embryos reach this stage of evolution.
When do we use this technique?
When we have achieved good embryos in the previous cycles but they have not implanted.
Where a patient only wants to transfer one embryo to prevent a multiple pregnancy.
When we have to undertake Preimplantation Genetic Diagnosis through a trophoblast biopsy.