Third-generation IVF technology — Preimplantation Genetic Testing (PGT) helps give your child a healthier start

PGT requires the embryo to be cultured to the blastocyst stage (EKI-IVF typically cultures to day 5–7), after which a small number of cells are biopsied from the trophectoderm (the portion that will develop into the placenta) to avoid damaging the inner cell mass (the portion that will develop into the fetus). Results usually take 7 to 14 days (longer for monogenic disorders); therefore all embryos are frozen and, after the screening results are available, the embryos that pass are thawed and transferred in a later cycle.

Categories & Who It Is For

This technology is designed to select, before transfer, embryos that are euploid, do not carry a specific disease-causing gene, or do not carry a specific chromosomal structural abnormality—thereby improving pregnancy success and reducing genetic risk. It is suitable for those who need chromosomal aneuploidy screening due to advanced maternal age, recurrent implantation failure, or recurrent miscarriage; for those who desire sex selection; and for those who carry a monogenic disease-causing gene or a chromosomal structural rearrangement.

Based on the guidelines of the European Society of Human Reproduction and Embryology (ESHRE) and international standards, PGT is mainly divided into the following three categories according to its testing target and clinical application.

PGT-A (Chromosomal Aneuploidy Screening)

* Screening goal: Detect whether the embryo’s 23 pairs of chromosomes are abnormal (aneuploidy). The core purpose is to reduce the risk of miscarriage caused by embryonic chromosomal aneuploidy and to significantly improve the live birth rate per transfer.

* Who it is for:

*   Advanced maternal age: female age usually ≥ 38, where the risk of embryonic chromosomal abnormality increases significantly with age.

*   Recurrent implantation failure: patients who have undergone multiple embryo transfers without successful pregnancy.

*   Recurrent miscarriage: two or more unexplained miscarriages, possibly related to embryonic chromosomal abnormalities.

*   Sex selection needs: suitable for sex selection.

PGT-M (Monogenic Disease Screening)

*   Screening goal: On top of PGT-A, targets monogenic diseases that are clearly diagnosed and confirmed by family analysis. While ensuring normal chromosome number, it selects embryos that do not carry the specific disease-causing mutation, thereby blocking the transmission of monogenic diseases within the family.

*   Who it is for:

Patients or carriers of monogenic genetic diseases: families where one or both partners carry a defined monogenic pathogenic variant and are at risk of having an affected child.

Including but not limited to:

*   Autosomal dominant disorders.

*   Autosomal recessive disorders (e.g., beta-thalassemia, spinal muscular atrophy).

*   X-linked disorders (e.g., Hemophilia A/B).

PGT-SR (Chromosomal Structural Rearrangement Screening)

* Screening goal: Detect whether the embryo’s chromosomes have structural abnormalities. For couples carrying a balanced translocation or inversion, their gametes (sperm or egg) are prone during meiosis to produce gametes with duplicated or deleted chromosomal fragments, leading to embryonic chromosomal imbalance and recurrent miscarriage or implantation failure.

*   Who it is for:

*   Either partner is a carrier of a chromosomal structural rearrangement, including:

*   Balanced translocation (reciprocal translocation).

*   Robertsonian translocation.

*   Chromosomal inversion (e.g., pericentric or paracentric inversion).

Special reminder:

Although the clinical accuracy of PGT as an embryo screening technology can exceed 99%, it cannot 100% rule out all potential genetic or developmental abnormalities. Therefore, after a successful pregnancy through PGT, regular prenatal check-ups and prenatal diagnosis as advised by your doctor are required.