What Is PGT-A?
PGT-A — preimplantation genetic testing for aneuploidies — is a laboratory technique that screens IVF embryos for chromosomal abnormalities before transfer. Chromosomal errors (having too many or too few chromosomes) are the leading cause of implantation failure, miscarriage, and certain genetic conditions. By testing embryos before transfer, PGT-A aims to identify the embryos most likely to result in a healthy pregnancy.
What It Screens For
PGT-A examines all 23 pairs of chromosomes for numerical abnormalities (aneuploidies). This includes conditions like Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Patau syndrome (trisomy 13), Turner syndrome (monosomy X), and other chromosomal imbalances that cause failed implantation or early miscarriage.
PGT-A is specifically used for screening embryos for chromosomal conditions that affect viability and health. For patients with known genetic diseases in their family — such as cystic fibrosis, sickle cell disease, or Huntington's disease — a different test called PGT-M (preimplantation genetic testing for monogenic disorders) can screen for specific inherited conditions.
PGT-A and PGT-M are medical screening tools designed to identify chromosomal abnormalities and inherited genetic diseases. In Colombia, these tests are used to support healthy pregnancies and prevent genetic disease transmission — consistent with their intended medical purpose.
Who Benefits Most
PGT-A is not necessary for every IVF patient, but research suggests it offers the most benefit for women over 37, where aneuploidy rates increase significantly with age, patients with recurrent pregnancy loss, where chromosomal abnormalities may be a contributing factor, patients with recurrent implantation failure after multiple transfers, and patients with a history of chromosomally abnormal pregnancies.
For younger patients with no history of pregnancy loss, the benefit of PGT-A is less clear-cut. Some studies show improved per-transfer success rates with PGT-A, while others suggest that cumulative success rates (across multiple transfers) may be similar with or without testing.
How It Works
PGT-A requires embryos to be cultured to the blastocyst stage (day 5–6), at which point a small biopsy of 5–10 cells is taken from the trophectoderm (the outer layer that becomes the placenta). The embryos are then vitrified (frozen) while the biopsy samples are sent to a genetics laboratory for analysis. Results typically return within 1–2 weeks, and the patient can then proceed with a frozen embryo transfer of a chromosomally normal (euploid) embryo.
This process requires a freeze-all approach — fresh transfer is not possible when PGT-A is performed because results take time.
Cost
PGT-A in Colombia typically costs $1,000–$2,000 depending on the number of embryos tested. This is significantly less than the $3,000–$6,000 charged by US laboratories. The test adds to the overall cycle cost, but for patients in the target groups, it can save the emotional and financial cost of transferring embryos that were unlikely to succeed.
The Debate Around PGT-A
PGT-A is a valuable tool for the right patients, but it's not universally necessary. Discuss with your physician whether testing makes sense for your specific age, medical history, and number of embryos available. The goal is to make informed decisions about which embryos to transfer — not to pursue testing as a default.
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