What really is PGT-A?
Preimplantation genetic testing for aneuploidy (PGT-A) is simultaneous testing of the entire set of chromosomes of an embryo on the day 5 of development by NGS method (Next generation sequencing) before the embryo is transferred into the uterus. PGT-A makes it possible to choose the best and most viable genetically competent embryos, thus effectively increasing the rate of implantation, clinical pregnancy and successful birth.
Who is recommended for such testing?
High risk of the development of aneuploid embryos (with altered chromosome number) in case of parents with normal somatic karyotype:
- Women over 37 years
- Women over 35 years, if good morphology embryos develop, but pregnancy fails to occur
- Infertility of unexplained etiology in young couples
- Two or more unsuccessful IVF cycles (transfer of five or more embryos)
- A history of two or more spontaneous abortions (including the missed abortion)
- Decreased sperm quality of the partner (oligoasthenoteratozoospermia, severe oligozoospermia or azoospermia, poor sperm morphology, high DNA fragmentation)
In case of altered karyotype in parents (one or both) or if there is a high risk of passing a genetic disorder to the child:
One or both parents are carriers of balanced chromosomal aberrations (Robertsonian or reciprocal translocations)
Male infertility factor associated with AZF microdeletions (Y-chromosome)
One or both parents are carriers of X-chromosome mutation (risk of development of e. g. Duchenne/Becker muscular dystrophy, fragile X chromosome syndrome, haemophilia and other disorders)
PGT-A – step by step
IVF/ICSI manipulation
Cultivation of the received embryos up to day 5 (blastocyst)
Embryo biopsy – several trophectoderm (outer layer) cell collection without harming the embryo and without any damage to its further development – to determine whether this embryo is healthy and suitable for transfer
Embryo freezing (vitrification) for later use
PGS – Preimplantation Genetic Screening – Chromosomal analysis
Selection of genetically competent embryos for embryo transfer
Embryo transfer
How to get the answers?
A molecular geneticist together with a clinical geneticist, having received the results of testing by the NGS method, examine them and make a decision on each of the embryos. There are results where the answer is absolutely clear – the embryo is valid or not. However, there are embryos in which mosaic changes have been identified. This means that in the trophectoderm of a particular embryo from which the material was taken, the set of chromosomes was changed only in the part of the cells. And sometimes, if the conclusion about the quality of the embryo is on the border between “valid for transfer” and “not valid for transfer”, only the experience and knowledge of molecular geneticist, geneticist and reproductologist allow us to make a joint decision on the suitability of such an embryo for medical fertilization.
Who carries out this testing in Latvia?
We are the only clinic in Latvia who performs Preimplantation genetic testing on site, in our own laboratory. The iVF Riga Genetic centre began his work in 2014, and already in 2015, the first child was born after PGT-A.
We perform PGT-A and PGT-M testing for other Latvian and foreign clinics.
Conclusion
Much is being talked about is it necessary to make PGT-A or not? But the main question is: does this method really help – and for whom?
At the moment, we have tested 2616 embryos. On average, we test 100 embryos per month, and from our own experience, we see that PGT-A testing improves the success rate of IVF cycles. Therefore, we recommend this method to save you from unnecessary worries and help to achieve the desired results as soon as possible.
So, PGT-A is carried out:
- to screen the entire set of chromosomes for abnormalities;
- to improve IVF results;
- to increase IVF success rates;
- to help patients with repeated abortions;
- to help patients with fail implantation after an IVF cycle.
Three conditions are required for the complete and effective use of this method:
- a high-quality equipment and experience in testing;
- a team of specialists to have the possibility of double-checking;
- a concilium of clinical geneticists, experienced reproductologists who can make a decision on each embryo and on the detected changes.
