Preimplantation genetic testing (PGT) is a very useful tool in the field of Assisted Reproduction, allowing couples to improve their chances of conceiving a healthy baby. In particular, PGT for aneuploidy (PGT-A) focuses on identifying and selecting embryos that possess an adequate number of chromosomes, thus minimising the risk of genetic disorders due to aneuploidy and facilitating a successful pregnancy in the fewest number of transfers possible.
Aneuploidies are genetic alterations that occur when an embryo has an abnormal number of chromosomes, the structures in which our DNA is organised. This chromosomal imbalance in embryos is more represented in couples with some conditions, such as advanced age in the woman or the existence of a severe male factor, and can produce serious conditions such as Down syndrome (trisomy 21), Edwards’ syndrome (trisomy 18) and Patau’s syndrome (trisomy 13), among others.
The Role of PGT in Aneuploidy Detection
PGT-A is a highly specialised technique performed during an in vitro fertilisation (IVF) cycle. After fertilisation of the oocytes with sperm, the resulting embryos are biopsied at the blastocyst stage, usually at the blastocyst stage, where cells are removed from the embryo and their genetic material is analysed to determine the number of chromosomes.
This accurate analysis allows the selection of euploid embryos, i.e. those with the correct number of chromosomes, significantly improving the chances of a successful pregnancy and reducing the chances of miscarriage.
Indications for PGT-A
PGT-A is indicated for couples facing certain risk situations, such as:
- Advanced maternal age: As the woman’s age advances, the likelihood of chromosomal abnormalities in the eggs increases, which increases the likelihood of aneuploid embryos. In these situations, PGT-A becomes essential for older women seeking to conceive a healthy baby.
- Severe male factor: Severe alterations in the sperm quality of the male may contribute to an increase in the aneuploidy of the embryos obtained. As in the case of advanced maternal age, PGT-A will be indispensable to identify euploid embryos.
- Repeated miscarriages: If a couple has experienced repeated miscarriages, aneuploid embryos are a possible cause. The application of PGT-A can help to identify and select euploid embryos for implantation.
- Previous IVF treatment failures: If the couple has had previous unsuccessful IVF cycles, the presence of aneuploidy may be a factor. PGT can improve the chances of success in future IVF attempts.
PGT-A: a shortcut to pregnancy
PGT-A offers couples the hope of conceiving a healthy baby in a straightforward way. In addition, pregnancy and delivery rates are significantly higher in PGT-A cycles compared to conventional cycles, according to data from the SEF (Spanish Fertility Society). PGT-A identification of embryos with adequate chromosomal endowment helps couples by reducing the emotional and financial burden associated with miscarriages. This is made possible by minimizing the number of transfers needed to find a euploid embryo thanks to PGT-A.
In conclusion, preimplantation genetic testing for aneuploidy represents a significant advance in reproductive medicine. This technique offers couples the possibility of identifying chromosomally healthy embryos, thus increasing the chances of a successful pregnancy and reducing waiting time and promoting conscious parenthood.