Embryos obtained after In Vitro Fertilization may remain on special culture media and be transferred five days after follicle aspiration, when they have developed to an embryonic stage called blastocyst. This strategy, used in the appropriate patients, improves pregnancy rates.

 On the 5th day of development the embryos have overpassed a critical stage in their development (after the 3rd day of culture) where some stop growing because they have chromosomalabnormalities. Unlike other techniques such as PGD, long term embryo culture allows the selection of  embryos with the least possible biological stress, avoiding a decrease in their ability to implant. The daily morphological visualization of embryos allows embryologists to select the embryo/s with the greater ability to give birth to a healthy baby.

This tool is indicated to:
1. Patients that because of their age, ovarian stimulation response or number and quality of embryos obtained, can benefit from embryo selection in the blastocyst stage.
2. Couples with repeated implantation failures, ie, who have completed at least 2 transfers with good quality embryos transferred on the third day of development and have not achieved a pregnancy.
3. Couples with repeated miscarriages.