PGT-A (Preimplantation Genetic Testing for Aneuploidy) examines embryos for chromosome-number abnormalities before they are transferred to the uterus. A healthy embryo carries 46 chromosomes; a missing or extra chromosome (aneuploidy) is the most common reason for implantation failure, miscarriage and chromosomal disorders.
How is it performed?
Embryos are cultured to day 5-6 (blastocyst stage). A few cells are taken from the outer layer that will form the placenta (trophectoderm) — not the baby — and sent for genetic analysis. In experienced hands the biopsy does not affect the embryo’s potential; embryos are vitrified until the results arrive.
Who is it recommended for?
- Women aged 37 and over: aneuploidy rates rise significantly with age
- Couples with recurrent miscarriage
- Recurrent implantation failure despite good-quality embryos
- Severe male-factor cases
What to expect — and what not to
PGT-A increases the pregnancy rate per transferred embryo and lowers the miscarriage rate; but it does not make your embryos “better” — it only helps select the healthiest one. In patients with few embryos the test is not always an advantage; the decision should be made with your doctor, weighing age, embryo numbers and history together.