Causes & Treatment
What is PGT IVF, and is it necessary? A fertility clinic answers your questions
Team TRB in partnership with Dr Laura Garcia, Medical Director at Clinica Tambre | 2 May 2020
Your PGT IVF questions, answered
When we asked our community what they wanted to learn more about from our expert partners, the answer was clear: PGT IVF.
So, we opened up the conversation on Instagram and collected your top questions. Then we took them straight to the trusted team at Clínica Tambre — a leading fertility clinic based in Madrid, Spain.
Over the years, we’ve built a library of resources together with their world-renowned clinical team, covering topics like:
- How to navigate switching fertility clinics
- Understanding antral follicle count and fertility over 35
- Are egg donors anonymous in Spain? (Your most searched questions)
All caught up? Let’s dive into what Dr. Laura Garcia, Medical Director at Clínica Tambre, had to say about PGT IVF.
What is PGT / PGS / PGD – and is there a difference?
PGT (Preimplantation Genetic Testing) is an umbrella term that includes both PGS and PGD. It involves testing embryos – usually on Day 5 – by performing a biopsy to examine some of the embryo’s cells for genetic information.
- PGS (Preimplantation Genetic Screening), also called PGT-A, checks for aneuploidy – abnormal numbers of chromosomes in the embryo, which can affect implantation and development.
- PGD (Preimplantation Genetic Diagnosis), now typically referred to as PGT-M or PGT-SR, tests for specific inherited genetic mutations passed down from the mother or father.
What’s the difference between the types of PGT?
- PGT-A (formerly PGS):
Screens for chromosomal abnormalities (aneuploidy) in embryos – helps identify euploid (chromosomally normal) vs aneuploid embryos. - PGT-M (formerly PGD):
Used when one or both parents are known carriers of a specific single-gene (monogenic) disorder. It identifies embryos affected by that genetic condition. - PGT-SR:
Used when one or both parents have a structural chromosomal rearrangement, such as a translocation or inversion. It helps detect embryos with the correct chromosome number and structure.
Who might benefit from PGT?
- PGT-A (PGS):
May be recommended for women of advanced maternal age, those with a history of repeated miscarriage, or prior IVF failure. - PGT-M:
For individuals or couples who carry or are at risk of passing on a known genetic disease. - PGT-SR:
For individuals with known chromosomal structural abnormalities (e.g translocations) identified through karyotype testing.
What is genetic compatibility testing?
Genetic compatibility testing checks whether both partners carry mutations for the same recessive genetic conditions – such as cystic fibrosis or spinal muscular atrophy. Even if both partners are healthy, they may unknowingly carry genes for certain inherited conditions.
This test is recommended for all patients undergoing fertility treatment (including IVF, egg donation, or double donation), to help reduce the risk of passing on recessive genetic disorders to their children.
PGT IVF can be controversial – what’s your take?
It’s true that no medical test is 100 per cent definitive. But when there’s a high risk of producing embryos with chromosomal abnormalities (which can lead to miscarriage, certain syndromes, or failed implantation) it’s important to have a conversation with each woman or couple – focused on their individual situation – before starting treatment.
This includes walking them through the pros and cons of PGT IVF so they can make an informed decision.
What are ‘mosaic embryos’? Should they be transferred?
A mosaic embryo contains a mix of chromosomally normal and abnormal cells – some cells are genetically typical, while others aren’t.
Whether or not to transfer a mosaic embryo depends on several factors, including which chromosomes are affected. For example, abnormalities involving sex chromosomes or chromosomes 21, 13, or 18 are typically excluded.
The decision also takes into account how many chromosomes are involved and the specific nature of the abnormality.
Can testing harm the embryo?
PGT is an invasive test, so yes, there is a potential risk of harm. That’s why it’s crucial to have it done at an expert clinic, with advanced laboratory technology and experienced senior biologists handling the procedure.
Do people use PGT to find out the sex of their embryo?
In some countries, that may happen. However, speaking here for Clínica Tambre, sex selection through PGT is not allowed in Spain.
How much does PGT cost?
It varies depending on the type of genetic testing. For example, in PGT-A, the cost depends on how many embryos are biopsied. Our Patient Care team would be happy to give you more detailed information – just drop us an email at [email protected].
If someone has a low AMH, only a few embryos, and is over 40, would you still recommend PGT?
Women with low ovarian reserve or only one embryo tend to benefit less from PGT. However, since the likelihood of chromosomal abnormalities increases after age 40, it’s essential to have a thorough discussion, focused on the individual situation, to weigh whether testing makes sense in each case.
Thank you to Clínica Tambre for answering our readers’ questions about IVF and PGT. If you’re looking for more information or want to explore treatment options, their expert team is ready to help.
If you have any follow-up questions about PGT or related topics, feel free to send us a message on Instagram – our DMs are always open.
