Preimplantation Genetic Testing Help Increase the Success Rate in Fertility

Preimplantation Genetic Testing Help Increase the Success Rate in Fertility

For a couple who wants to have children but have not yet succeeded or have experienced miscarriage, there is an advanced technology that is being used together with IVF to help increase your chances of successful pregnancy. Technique is used to check the chromosome number of the embryo, it is called as Preimplantation Genetic Testing for Aneuploidy (PGT-A)

An embryo is created from a fertilization of one egg, which has 23 chromosomes and one sperm, which has 23 chromosomes. The embryo has a total of 46 chromosomes. Some embryos may have abnormal number of chromosomes, which is called aneuploid embryos. These aneuploid embryos do not usually implant, or if it does it will eventually ending up miscarried.


The advantage of preimplantation genetic testing are:

1. The doctor can determine which embryo has normal number of chromosomes -allowing the prioritization of embryo selection to increasing the chances of embryo implantation.

2. When a good embryo is selected first for a transfer -it reduces the chance of miscarrige (due to aneuploidy)

3. Because euploid embryos has a high chance of implantation and lower chance of miscarriage. PGT-A helps reduce the time it takes to become pregnant.

4. PGT-A reduce the chance of giving birth to children with abnormal number of chromosome, for example, the Down Syndrome which is caused by having an extra copy of chromosome 21.


Preimplantation Genetic Testing Steps

When the embryos reach the blastocyst stage in the day 5 they have approximately 150 cells. Our embryologists will delicately remove 3 – 5 trophectoderm cells (these cells will becomes placenta) and used for genetic testing. Removing a small amount of the trophectoderm cells does not interfere an embryo development.

After getting the cells the next step is to increase amount of embryonic DNA. The chromosome status of the embryos is determined by using Next Generation Sequencing technique (NGS) which allows doctors to know that which embryo has completely set of the chromosomes and select for a transfer to increases the chances of getting pregnant. The remaining embryos that have been examined by PGT-A can be kept frozen for use in future pregnancies.

Written by
Dr.Pornwaratt Niyomrattanakit
Genetics Laboratory Manager