PGT-A and IVF: when is embryo genetic testing recommended? 

An embryo can look healthy under the microscope and still carry chromosomal abnormalities that affect its ability to implant or develop into a pregnancy.

Preimplantation genetic testing for aneuploidy (PGT-A) is a genetic screening test performed during IVF to check the number of chromosomes in embryos before transfer.

PGT-A can add useful information when selecting embryos, particularly for patients of advanced maternal age, with repeated IVF failure, or with a history of recurrent miscarriage. When is it actually recommended, and who benefits most?

What is PGT-A?

PGT-A stands for preimplantation genetic testing for aneuploidy. It screens IVF embryos to check whether they have the expected number of chromosomes. A normal human embryo has 46 chromosomes.

• Euploid embryos have the expected number of chromosomes.
• Aneuploid embryos have an abnormal number of chromosomes.

Aneuploidy can prevent implantation, cause early pregnancy loss or stop an embryo developing normally. PGT-A identifies these abnormalities before transfer and adds information to guide embryo selection.

How does PGT-A work?

PGT-A is performed during an IVF cycle in six steps:

• Ovarian stimulation: hormonal medication stimulates the ovaries to produce several eggs.
• Egg retrieval and fertilisation: the eggs are collected and fertilised by IVF or ICSI.
• Embryo development: embryos are cultured to the blastocyst stage, usually day five or six.
• Embryo biopsy: an embryologist takes a few cells from the embryo’s outer layer.
• Genetic testing: the cells are analysed for chromosome number.
• Embryo selection: the results identify euploid embryos and guide which embryos are suitable for transfer.

Embryos are generally frozen while the testing is completed, and the transfer takes place in a later cycle.

When is PGT-A recommended?

PGT-A may be considered in selected IVF cases, particularly when embryo chromosomal abnormalities are more likely. Common situations include:

• Advanced maternal age, as the likelihood of embryo aneuploidy increases with age
• Previous miscarriages linked to chromosomal abnormalities
• Repeated unsuccessful IVF attempts with untested embryos
• Repeated implantation failure, where embryo aneuploidy may be a factor
• Several blastocysts, where more information would help choose between them

PGT-A is not routinely necessary for every IVF patient. Its benefits should be assessed individually.

Who benefits most from PGT-A?

Women of advanced reproductive age

As women get older, chromosomal errors during egg development become more likely, so a higher proportion of embryos may be aneuploid.

Patients with previous chromosomally abnormal pregnancies

Where testing of a previous miscarriage found aneuploidy, PGT-A can help identify embryos with the expected chromosome number before transfer.

Patients with repeated IVF failure

When previous cycles involved unsuccessful transfers of untested embryos, PGT-A can help establish whether chromosomal abnormalities may have contributed.

PGT-A and repeated IVF failure

One possible reason for repeated unsuccessful IVF cycles is embryo aneuploidy.

An embryo can look healthy under the microscope while carrying an abnormal number of chromosomes, which can stop it implanting and developing into an ongoing pregnancy.

For patients who have had repeated unsuccessful transfers of untested embryos, PGT-A gives information about the embryos’ chromosomal status. This helps the specialist judge whether aneuploidy contributed to previous failures and guides future embryo selection.

Repeated IVF failure has several possible causes, however. PGT-A does not address all of them and does not guarantee a pregnancy.

Can PGT-A help with recurrent miscarriage?

Chromosomal abnormalities are a major cause of early pregnancy loss. About 50–60% of first-trimester miscarriages are associated with embryonic aneuploidy, and the likelihood generally rises with maternal age.

An embryo can implant and give a positive pregnancy test but fail to develop normally because of an underlying chromosomal abnormality.

For patients with recurrent miscarriage, particularly when testing of a previous pregnancy found aneuploidy, PGT-A may be considered during IVF to identify embryos with the expected number of chromosomes.

Recurrent miscarriage is not always caused by embryo genetics. Other possible causes include:

• Uterine abnormalities
• Antiphospholipid syndrome
• Parental chromosomal rearrangements
• Certain hormonal or metabolic conditions

A full recurrent miscarriage evaluation should come before deciding whether PGT-A is appropriate. See after repeated miscarriage: why it happens and what can be done.

Does PGT-A guarantee a successful pregnancy?

No. PGT-A assesses embryo chromosome number, but it cannot guarantee implantation, pregnancy or a live birth.

Embryos reported as euploid can still fail to implant or miscarry. Uterine health, embryo development and maternal health also influence IVF outcomes. PGT-A is a tool that supports embryo selection, not a guarantee of success.

Considering PGT-A and IVF in Egypt?

For international patients considering IVF in Egypt, PGT-A can be discussed as part of an individual treatment plan.

Dr. Omar Aboali’s team reviews your reproductive history, previous IVF attempts and investigations to decide whether embryo genetic testing is appropriate. If PGT-A is recommended, the team guides you through each stage: stimulation, egg retrieval, embryo biopsy, genetic testing and frozen embryo transfer.

You can start with an online consultation and agree your treatment timeline before travelling. The same testing also identifies embryo sex, which is how gender selection through IVF works.