Blastocyst Culture refers to the process of growing the embryos in the laboratory for a longer period before transferring them to the uterus for implantation. It is a technique used in In Vitro Fertilization to maximize pregnancy rates and reducing the risk of multiple pregnancies.
In a traditional IVF procedure, the embryos are transferred to the womb on Day 3 after fertilization. In most cases embryos are transferred. An embryo that is cultured in the laboratory for 5-6 days after fertilization is known as blastocyst. In this stage the embryo has divided multiple times and has approximately 50 – 200 cells. They have a very thin outer shell which makes implantation in the uterus easier. Typically most of the fertilized eggs make it to the three day embryo stage whereas only 40% of them only make it to the blastocyst stage. Since these blastocysts are a more advanced stage, they have a higher chance of pregnancy. Since fewer embryos are transferred in this process, it greatly reduces the risk of multiple births. The procedure is same as that of IVF, except that the embryos are cultured for a longer period in the laboratory. The process does not improve the quality of the embryo in any way, it simply helps to select the best embryo.
ADVANTAGES OF BLASTOCYST CULTURE
- Higher Implantation Rate (though it is also dependent on maternal age and infertility conditions).
- Provides opportunity to select the most viable embryo for transfer
- Embryos are transferred at the right place at the right time. According to some , the conditions in the womb are more favourable for the blastocyst.
- In cases where single embryo transfer is preferred by the patient such as concern of multiple pregnancies, uterine anomalies etc
- In case of large number of frozen embryos, it becomes difficult to choose the most viable embryo. In such cases the embryos are thawed and cultured through the blastocyst stage and the most appropriate blastocyst is transferred.