has helped many families with genetic diseases give birth to healthy children, making their families happier and more perfect. So, what is the third-generation IVF? What are the methods for blastocyst biopsy in the third-generation IVF? The following is an introduction by the Baomei from Aibaolai.
1. What is the third-generation IVF?
The third-generation IVF technology is also called preimplantation genetic diagnosis/screening (PGD/PGS), which refers to the embryo transfer before IVF-ET embryo transfer Analysis of genetic material, diagnosis of abnormalities, screening of healthy embryo transfer, and methods to prevent the transmission of genetic diseases. What are the several methods for blastocyst biopsy in the second and third generation test tubes:
1, blastocyst trophoblast cell biopsy
blastocyst trophoblast cell biopsy is now the third generation test tube technology is more commonly used. Embryos cultured in vitro will usually develop to blastocysts on the 5th and 6th day. At this time, the number of cells in the embryo increases significantly, reaching more than 100. The trophoblast cells of the blastocyst will develop into the placenta or fetal membrane in the future and will not participate in the formation of the fetal part. Therefore, the trophoblast cells of the biopsy blastocyst can not only reflect the genetic information of the embryo to the greatest extent, but also avoid damage to the fetus. The number of cells that can be obtained from blastocyst trophoblast biopsy is increased, and the proportion of chromosome mosaicism in blastocyst stage embryos is significantly lower than that of cleavage stage embryos, which improves the accuracy of genetic diagnosis; at the same time, blastocyst culture technology and vitrification The increasingly mature melting technology and the development of laser instruments also provide technical support for the wide application of blastocyst biopsy.
2, polar body biopsy of oocytes
early IVF third-generation technology selects cell polar bodies for biopsy. This is because the uneven division of oocytes will produce polar bodies, which have nothing to do with the development of the final embryo and have no known functions, so polar bodies can be used as biopsy materials. The advantage of polar body biopsy is that it will not affect the normal development and fertilization of egg cells; and the sampling is earlier, and the time for examination and analysis will be more abundant; but the disadvantages are also obvious. The source of polar body is oocyte, so it can only distinguish maternal genes and chromosomes. , But unable to analyze paternal chromosomal abnormalities. Z1z
3, blastomere biopsy at the cleavage embryo stage
The egg and sperm form a zygote after fertilization, and then cleavage, which can reach the 6-10 cell stage by the third day of culture. Turn on transparency at this time, and aspirate one or two blastomeres from the embryo for genetic testing. The remaining blastomeres will continue to develop, and the removal of one or two blastomeres will have little effect on the further development of the embryo. However, the material obtained by this method is too small, and because the embryo may have a certain degree of mosaicism, at this time, the detection of a single blastomere of the cleavage stage embryo does not represent the state of the entire embryo. Therefore, aneuploid mosaicism of embryos will lead to missed diagnosis and transfer of abnormal embryos.
A warm reminder from Aibaolai’s Baomei: With the maturity of the third-generation IVF technology, the most commonly used blastocyst biopsy is the trophoblast cell biopsy of the blastocyst. This is not only a more accurate check, but also a certain guarantee for the healthy development of the blastocyst. .
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