In IVF treatments, embryos that are developed in the lab for 5 days are called blastocysts. The process of transferring embryos on day 5 is called blastocyst transfer. The first successful IVF treatment in 1978 included the blastocyst transfer. The embryo reaches the blastocyst period on day 5-6. A blastocyst includes around 100-120 cells. After this development period, embryos cannot be hold in the laboratory and that is why it is the last phase of embryo transfer in to the mother’s uterus.
In IVF treatments, especially in patients with a good egg reserve it is generally possible to obtain many embryos. It is difficult to understand which of the embryos are suitable to transfer on day 3. After this phase, the embryos are hold for two more days in the lab to obtain blastocysts in order to be able to choose strong embryos.
Specifically in egg donation and embryo donation treatments, it is possible to obtain many embryos as we use donor eggs. The correct and most suitable embryos will be selected on day 5 in order to be able to transfer blastocysts. Another advantage of using blastocyst transfer is the chance of obtaining embryos that do not have chromosomal abnormalities, as it is very difficult for the embryos with chromosomal disorders to be able to survive to day 5.
Blastocyst transfer which is one of the most advanced techniques used by our centre done on day 5 in our IVF Centre provides high chances of positive pregnancies for couples who are doing treatments.
Blastocyst transfer is done 5 days after the oocyte collection day; patients have the possibility to freeze the remaining embryos for a future pregnancy.
Women who have been transferred at least one blastocyst will have 65% of chance to have a live birth. The transfers obtained on day 2-3 will have 20% chance of having miscarriages whereas the chance of miscarriage on transfer done on blastocyst stage is 5%. Although there are many advantages of blastocyst transfer, we can only decide to do a blastocyst transfer on the third day of the treatment by looking at the quality of the embryos. Additionally if the patient wants to avoid multiple pregnancy, only one or two embryos that are on blastocyst stage would be enough.
In order to be able to obtain a blastocyst transfer, apart from having good quality and quantity of embryos would not be enough. The laboratory conditions, the design, hygiene and periodical checks as well as periodical calibrations of the machines should be done correctly. The equipment used by the centre is essential for the success of the treatment as well as experienced embryology personnel should be present in the centre.
What are the advantages of using blastocyst transfer?
- As the embryos develop in the lab until the last moment, the healthiest embryos with the highest quality are selected.
- s the embryo grow, it would be easier for it to implant in to the uterus.
- Research show that blastocyst transfer increase the possibility of positive pregnancies.
- As many embryos are not transferred in the blastocyst transfer, it is possible to avoid multiple pregnancy.
What are the disadvantages of using blastocyst transfer ?
- In 40% of the patients, it is not possible to obtain blastocysts.
- In some cases freezing on day 5 will not give the same positive results as freezing on day 3.
- Some research show that 10% of embryos that are not able to reach the blastocyst stage in the lab could continue to develop in the uterus.
