IVF information · 9 / 9
Preimplantation genetic testing
Preimplantation genetic testing (PGT) is a group of tests that can be done during IVF to examine the genetic makeup of embryos before transfer. Next-generation sequencing (NGS) is a technology used in these tests.1
PGT-A (aneuploidy)
PGT-A looks at the number of chromosomes. Abnormal chromosome numbers can be associated with implantation failure, miscarriage or conditions such as Down syndrome. A few cells are taken from the embryo, usually at the blastocyst stage (day 5 or 6), and analysed in the laboratory.1 Embryos with a normal chromosome count are considered for transfer.
PGT-M (monogenic disorders)
PGT-M is used when a specific single-gene condition, such as cystic fibrosis or sickle cell disease, runs in the family. The gene concerned is analysed in cells taken from the embryo, and embryos without the mutation are considered for transfer.1
PGT-SR (structural rearrangements)
PGT-SR is used when one or both parents carry a structural chromosome change, such as a translocation or inversion, which may lead to unbalanced chromosomes in the embryo. Cells taken from the embryo are analysed to see whether the embryo is affected.1
Points to consider
- PGT is not necessary for everyone.2 Whether it is suitable depends on the medical and family history.
- The test has limits, and a normal result does not guarantee a pregnancy or a healthy baby.1
- A biopsy involves taking cells from the embryo. Genetic counselling is recommended before deciding.1
References
- ESHRE PGT Consortium Steering Committee, Carvalho F, et al. ESHRE PGT Consortium good practice recommendations for the organisation of PGT. Human Reproduction Open. 2020;2020(3):hoaa021.
- ESHRE Add-ons Working Group. Good practice recommendations on add-ons in reproductive medicine. Human Reproduction. 2023;38(11):2062–2104.
Related topics
- What is infertility and in vitro fertilization?
- Pre-assessment before IVF
- When is IVF considered?
- Starting the treatment
- Ovarian stimulation and monitoring
- Steps in IVF treatment
- Practices before and during IVF
- Recommendations during treatment
- Embryo development and the blastocyst stage
- Frozen embryo transfer
- Male infertility and sperm retrieval
This page gives general information only. It does not replace an examination, and the treatment plan is decided by the physician for each person individually.