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On the occasion of World IVF Day, Dr Satish Patki as senior IVF consultant of Patki Hospital and Dr Sam Balu, Head of Genomics Department at Lilac Insights, India’s leading genetic diagnostic testing Company jointly announced the path breaking technology in IVF (Test TubeBaby) treatment called “Non Invasive Chromosomal Screening (NICS)”of the preimplantation blastocyst embryos.
NICS on the other hand is an entirely noninvasive procedure where the embryo remains untouched. Normally, the embryos are cultured in the incubator for 5 days individually in a small droplet of 20 to 30 microlitres of the culture medium, arranged in a petri dish.
NICS technology can prove revolutionary in the treatment of IVF as it will improve chances of pregnancy since only euploid embryos are transferred and the chances of them being implanted are high. It is especially beneficial for patients above 35 years, as the incidence of having aneuploid embryos is higher in them.
NICS can avoid transfer and subsequent implantation of such aneuploid embryos, resulting in poor pregnancy outcome in the form of abortions or chromosomal abnormalities in the babies like being born with Down syndrome.
IVF (in vitro fertilization) is an already established treatment for infertile couples where eggs of the woman/female is fertilized with the male’s sperms in a laboratory and then cultured in the incubator. The most mature form of the embryo, in the form of a ball of multiple cells with a fluid filled cavity called blastocyst is developed on the fifth day, after retrieval of eggs.
It is proved that about 30-40% of the embryos developed during IVF are chromosomally abnormal (aneuploid). Hence after transfer of such embryos to the mother’s womb, they are rejected by nature and only chromosomally normal embryos (euploid) get implanted, provided the uterus is receptive.
Presently, the technology which detects the chromosomal status of the blastocyst called Pre-implantation Genetic Testing (P.G.T.) is invasive. In PGT, few cells from the blastocyst are removed by a small needle (embryo biopsy) under the microscope with the help of laser technology and then these cells are subjected for the chromosomal evaluation. However, this procedure has disadvantage of being invasive and traumatic to the embryo and can lead to embryo damage. Additionally, it needs a skilled embryologist to perform the procedure and high end instrumentation involving the laser machine.
During this period of culture, cell free DNA from the blastocyst cells migrate to the culture medium in the droplet. In the process of NICS, 20 microlitres of this culture medium is taken for the analysis of the chromosomal make up of the embryo, without disturbing the embryo. The blastocyst is frozen and preserved for the procedure of embryo transfer later. Usually, during the IVF treatment cycle, 6 to 8 eggs are retrieved which result in the final formation of 3 to 4 blastocysts. The blastocyst which shows euploid (normal) pattern is selected for transfer.
Presently, in many IVF centers 2 or more blastocysts are transferred to the mother’s womb in the hope of getting implantation of at least one. However, on many occasions it results into twin or multiple pregnancy, which is medically considered as a high risk pregnancy due to its association with higher incidence of complications like abortion, preterm delivery, hypertension during pregnancy and low birth weight babies, requiring NICU care. NICS can guide the IVF specialist to transfer single euploid blastocyst avoiding multifetal pregnancy.
“Interestingly five patients have positive pregnancy results after transferring NICS tested euploid blastocysts. The remaining N.I.C.S. tested blastocysts are frozen and will be transferred soon,” said Dr SatishPatki, senior IVF consultant, Patki Hospital.
Dr Sam Balu, head of genomics at Lilac Insights stated that “Non-Invasive Chromosome Screening in IVF embryos is a game changer. The Sure test (brand name of the Non-Invasive Chromosome Screening test) could be offered as a routine non-invasive screening test for chromosome number for most IVF embryos. This is in sharp contrast to the current practice wherein only a few selected embryos are screened using PGT-A, as this method is expensive because it requires a laser, the biopsy process is time consuming and it is also traumatic to the embryo.”
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