Next Generation Sequencing

PGT-A (Pre-implantation Genetic Testing for Aneuploidy)
by NGS (Next Generation Sequencing) 

PGS allows for the screening of embryos during In Vitro Fertilization (IVF) in order to identify numerical chromosomal abnormalities (aneuploidy). NGS (Next Generation Sequencing) is the most advanced technology to perform the PGS test.

NGS Technology Advantages

  1. Analyze of all 23 pairs of chromosomes Comprehensive chromosome screening;

  2. The accuracy of NGS testing is 99%;

  3. Ability to detect aneuploidies, partial (segmental) aneuploidies (duplication/ deletion), mosaicism, unbalanced translocations, and some polyploidies with high sensitivity and specificity;

  4. Can be performed with day 5 or 6 embryos;

  5. Embryos are able to be transferred frozen.

  6. Detect the following disorders and conditions:​​

  • Trisomy 21 (Down syndrome), Risk of embryo implantation failure (Monosomies);

  • Trisomy 18 (Edward syndrome), Risk of miscarriages (Trisomies of chromosomes 2, 7, 15, 16, 17, 22);

  • Trisomy 13 (Patau syndrome), Risk of miscarriages (duplication/deletion);

  • 45,X (Turner Syndrome);

  • 47,XXY (Klinefelter Syndrome);

  • 47,XXX (Triple X syndrome);

  • 47,XYY (Jacob’s syndrome).

The NGS-based PGS benefits

  1. Improves implantation rates;

  2. Reduces miscarriage rates;

  3. Increases ongoing pregnancy;

  4. Fewer cycles of IVF treatment needed (less time and money);

  5. Greater chance of having a healthy baby.

Who should use NGS-based PGS test?

  1. Women over the age of 35;

  2. Women with 1 or more miscarriages;

  3. Couples with repeated IVF failure;

  4. Couples challenged by male factor infertility, with considering a low quantity and/or quality of sperm;

  5. Women with a previous pregnancy with fetal chromosome abnormality;

  6. Concern for a sex-linked gender illness.

The NGS-based PGS Process

  • IVF Couple undertakes In Vitro Fertilization (IVF) cycle to create embryo;

  • Embryo Biopsy (Day 5 or 6) The highly skilled embryologist carefully removes a small cell sample from each embryo;

  • NGS-base PGS Analysis All 23 pairs of chromosomes in the embryo are analyzed to determine to determine healthy, normal number of chromosomes;

  • Embryo Transfer A chromosomally normal embryo is selected for transfer back in the womb. Additional embryos with normal number of chromosomes can remain frozen for future use.


  • 23 pairs of chromosomes PGS by NGS cannot detect low level mosaicism, some polyploidies, balanced changes within (inversion) or between (translocation) chromosomes. 

  • PGS is limited by the technology and the number of cells examined. If the biopsied cells are normal it doesn’t necessarily mean that every cell in the embryo is also normal. The embryo could be mosaic, and depending on the severity, it may be unable to develop normally after transfer. Ongoing pregnancies are strongly recommended to undergo routine prenatal diagnosis.