Blastocyst Transfer

Q. What is Blastocyst ?
In nature, the fertilization of the egg takes place in the fallopian tube of the woman. It starts developing and the large single cell egg starts deviding in to 2 cell (day1), 4cell (day2), 8cell(day3) then it acquires a shape of ball of cells- called Morula on day 4. These cells then merge into each other.Eventually, a fluid filled cavity developes in this ball and the cells start arranging in a definite pattern forming outer layer - trophectoderm, a little mass of compact cells - the Inner Cell Mass or ICM and a large cavity called blastocoel. At this stage of development the embryo is called as Blastocyst. During this period of development, the fallopian tube keeps on pushing the embryo towards the uterus. Thus, the Blastocyst is the stage when the embryo enters the uterus by day 5/6.

Q. What is Blastocyst culture ?

The nutrition requirement of deviding embryos keeps on changing. Earlier, the culture media were able to support the growth of embryos only upto day 2/3 post-fertilization and therefore, the Embryo Transfer to the patient's womb had to be done on or before day 3 of fertilization.

Continuous research in the area of human embryo culture in the laboratory led to the designing of better culture media and laboratory conditions which made possible to grow the human blastocysts in lab conditions successfully and regularly.

Thus, now we can offer Blastocyst Culture to our patients. 

Q. Why Blastocyst culture ? What is the advantage ?

As mentioned above, the Blastocyst is the stage when the embryo enters the uterus. Now, it comes out (hatch out) of its outer envelope and is ready to implant. The environment in the uterus is more suitable for Blastocyst compared to cleaving stage embryos. This means by transferring Blastocyst on Day 5 or 6 we mimic the natural process.

Further, not every embryo has the potential to reach upto Blastocyst. Therefore, this extended culture of embryos in lab conditions offer a selection of only those embryos which have potential of sustained growth.
 
Since, Blastocyst is more likely to be implanted than the day 2 /day 3 embryos, we can reduce the number of embryos to be transferred. In fact, transferring just one embryo has become a norm in many countries. This helps us reducing the risk of multiple pregnancy and the complications thereof.