Genetic screening tests PGS-NGS (PGT-A)

Pre-implantation Genetic Screening (PGS) is used to detect numerical or structural anomalies in the chromosomes of embryos. The embryos are tested before they are transferred to the uterus.

Chromosomal anomalies:

  • are the most common causes of unsuccessful embryo implantation, resulting in lack of pregnancy;
  • are the most common cause of miscarriages in humans;
  • if the pregnancy is not miscarried, they may lead to a stillbirth, or a birth of a child with severe physical and/or mental problems.

Indications for PGS-NGS (PGT-A):

  • advanced age of the woman
  • patients after repeated implantation failure (RIF)
  • recurrent pregnancy loos (RPL)
  • severe male infertility factor
  • giving birth to a child with an innate defect


  1. Collection (biopsy) of blastomeres during the in vitro procedure

An embryo on day five should consist of several dozen cells (blastomeres). A special laser is used to make a hole in the embryo, and cells are collected for testing. The embryo is returned to the incubator, and frozen. The collected cells are analysed.

  1. Test / analysis of the collected blastomeres

The biopsied cells are analysed using a state-of-the-art technique called Next Generation Sequencing (NGS). Thanks to this method, the analyst may distinguish normal cells from genetically abnormal ones.

The goal of PGS (PGT-A) for aneuploidy is to provide a chromosomally normal embryo, thus increasing the chance of getting pregnant and reducing the risk of miscarriage or giving birth to a child with diseases associated with aneuploidy (e.g. Down syndrome).