What is a blastocyst transfer?
The blastocyst is an advanced embryo that has developed over five to six days after fertilisation. At this stage, the blastocyst has two distinct cell lines, called the inner cell mass (ICM) and trophectoderm. The ICM contains cells that eventually give rise to the fetus whereas the trophectoderm will form key cells of the placenta.
Blastocyst transfer is a strategy in which embryos are cultured to the blastocyst stage before being transferred to the womb. Once delivered into the uterine cavity, the blastocyst starts to attach to the uterine lining in a process known as implantation.
Higher pregnancy rates are associated with blastocyst transfer as compared to cleavage-stage embryo. As such, fewer blastocysts are transferred and hence the risks for multiple pregnancies are lowered. With these benefits, we often recommend patients to opt for extended culture in most circumstances. Blastocyst culture and transfer is done routinely in Alpha IVF Centre and is an important part in achieving good pregnancy rates for our patients.
What are the advantages of blastocyst transfer?
Not all embryos have the potential to develop into a blastocyst, either in the womb or in the laboratory. Therefore, blastocyst culture is a valuable tool to facilitate the selection of the best embryos that would be most likely to produce a pregnancy. By allowing extended culture for several days, we will be able to ‘de-select’ embryos that are non-viable. Blastocysts of good quality are transferred or cryopreserved for future use.
What are the disadvantages of blastocyst transfer?
The ‘disadvantage’ is that fewer embryos will survive or grow to the blastocyst stage. Thus, there is a possibility that there may be no available embryos for transfer. One could also argue if the uterus is a better environment than the incubator for growth.
Is blastocyst transfer for me?
Blastocyst-stage extended culture and transfer should be considered if:
- You have produced good quality embryos in a previous IVF cycle but they failed to implant in the womb.
- You are concerned about risk of multiple pregnancy and wish to have only one embryo transferred.
- You have several good quality embryos on Day 3.
- You have explored other treatment options and want to assess the developmental potential of your embryos.
- You are young with a good prognosis for pregnancy from IVF.