What is Blastocyst Culture?
The term ‘blastocyst’ is used to describe an embryo into its fifth to seventh day of development after fertilization. A blastocyst embryo has two distinct types of cells in addition to a central cavity that is filled with fluid. This cavity is known as the blastocoele cavity.
Usually, during the course of an IVF or ICSI treatment, the embryo is transferred to the womb on the second or third day after fertilization. But with blastocyst culture and transfer, which is also known as prolonged embryo culture, the embryo is permitted to grow in the test tube baby center’s laboratory for a slightly extended length of time. This period is used to determine the strength of the embryo(s) and if they will keep developing normally. This process is also known as blastocyst grading.
When is Blastocyst Culture Recommended?
Blastocyst culture is offered as an option in the following cases,
- Couples who fail to conceive a child even after multiple rounds of IVF or IVF-ICSI and despite having high quality eggs are recommended to go for blastocyst culture as the treatment offers higher IVF success rates compared to day 3 embryo transfers. The technique further allows the fertility expert to examine the embryo for growth abnormalities from day 3 to day 6.
- Even couples who have high quality embryos on day 3 can consider going in for blastocyst culture. The embryologist can use this opportunity to let the embryos develop into blastocysts. Blastocyst implantation offers two advantages. First, embryo(s) with higher chances of successful implantation can be identified and second, transferring on day 5 ensures fewer number of embryos are transferred which greatly reduces the likelihood of multiple pregnancy.
- Couples who desire to prevent risks resulting from a multiple pregnancy tend to select Single Embryo Transfer. The conception rates of this technique rise significantly when combined with blastocyst transfer. While normally the embryo is transferred on day 3, it is done on day 5 with blastocyst culture. The extra couple of days before the transfer increase the chances of successful conception.
- Blastocyst culture can also be beneficial to couples opting for Preimplantation Genetic Diagnosis (PGD). PGD helps couples who suffer from a genetic disorder to increase their chances of giving birth to a healthy child. The technique involves extracting a couple of cells from the developing embryos which are then subjected to genetic evaluation. This helps in identifying and transferring only healthy embryos into the uterus.