How can PGT-A prevent aneuploidies in IVF?

An embryonic aneuploidy occurs when the embryo has an incorrect number of chromosomes—either too many or too few. Aneuploidy is not hereditary and therefore cannot be prevented. However, in the context of assisted reproduction, it can be detected before the embryo transfer. Thanks to preimplantation genetic testing for aneuploidies (PGT-A), it is possible to analyze the chromosomal status of embryos. Based on these results, the medical team can select embryos without chromosomal abnormalities for transfer.

Identifying chromosomal abnormalities before embryo transfer is an effective strategy to minimize risks. IVI’s PGT-A offers the highest level of accuracy, which translates into improved pregnancy rates.

Below, we’ll explain how this test is performed and why it stands out in the field, but first, let’s take a closer look at what aneuploidies are and how genetic testing works.

What are aneuploidies?

To better understand the importance of reproductive genetics, it’s essential to first define embryonic aneuploidy. Humans have 23 pairs of chromosomes—one copy inherited from each parent. Of these, the 23rd pair are the sex chromosomes, which determine biological sex, and the rest are autosomes. When an embryo contains all 23 pairs correctly, it’s considered euploid. If any chromosome has more or fewer copies, the embryo is considered aneuploid.

Aneuploid embryos are generally not compatible with the birth of a healthy baby. Most do not implant or fail to develop properly. In some cases, they may implant but result in early miscarriage. Less frequently, certain aneuploidies can lead to chromosomal syndromes such as Down syndrome, which is caused by an extra copy of chromosome 21 (trisomy 21). This is why, in assisted reproduction, testing to detect aneuploid embryos before transfer is so important.

Aneuploidies are fairly common, occurring both in natural pregnancies and in assisted reproductive treatments. Even in couples under age 35, up to one in three embryos may present chromosomal abnormalities.

What is the origin of embryonic aneuploidy?

When aneuploidy affects the entire embryo, it typically originates during gametogenesis—the formation of eggs or sperm. In this case, the chromosomal error occurs before fertilization, whether through natural conception or IVF.

Maternal age is a major risk factor for embryonic aneuploidy. As a woman ages, the likelihood of chromosomal abnormalities in her embryos increases significantly, especially after age 35. However, age is not the only factor involved.

How to detect aneuploid embryos?

While aneuploidy cannot be prevented, it can be detected before transferring an embryo to the uterus during fertility treatment. Reproductive genetics plays a key role, as explained by Dr Josep Pla, genetic advisor and coordinator of the Reproductive Genetics Unit at IVI RMA:

“Genetics plays a crucial role in embryo selection during assisted reproduction. It allows prospective parents to reduce the rib sk of passing on genetic conditions to their children. Preimplantation Genetic Testing (PGT) is the answer for many patients. These genetic studies help identify chromosomal or genetic abnormalities in embryos before transfer, reducing the potential genetic risk. PGT-A is a valuable tool to personalize and optimize fertility treatment, increasing the chances of a successful pregnancy and reducing the risk of genetic abnormalities in newborns.”

IVI’s PGT-A: benefits, why is it the best genetic test, characteristics

As explained above, Preimplantation Genetic Testing allows for the detection of genetic and chromosomal abnormalities before embryo transfer. IVI offers several types of PGT, including PGT-A, which specifically screens for chromosomal aneuploidies.

The technology behind IVI’s PGT-A is considered a benchmark in the field for its exceptional precision. This results in a higher number of accurately identified euploid embryos—minimizing false positives and false negatives—and leads to more viable embryo transfers, fewer miscarriages, and a greater chance of pregnancy.

What makes IVI’s PGT-A so accurate?

Unlike other tests, IVI’s PGT-A combines two types of genetic analysis. First, it evaluates the DNA quantity across thousands of points on each chromosome using advanced sequencing technology. Second, it analyzes numerous variations in DNA sequences.

Together, these data layers provide added value, including the detection of ploidy abnormalities such as triploidy (3 copies of each chromosome) and haploidy (only 1 copy).

Here are the main advantages of IVI’s PGT-A:

• Avoids transferring non-viable embryos
• Speeds up the time to pregnancy
• Delivers greater precision in identifying euploid embryos
• Offers the highest analytical performance, with the lowest false positive and false negative rates
• Supports elective single embryo transfer (eSET)
• Prevents cryopreservation of non-viable embryos
• Reduces miscarriage rates
• Does not impact embryo development
• Highly versatile—can be easily combined with other embryo genetic tests like PGT-M or PGT-SR

Thanks to the advanced detection capabilities of IVI’s PGT-A, it is possible to identify a wide range of chromosomal conditions, including

• Whole chromosome aneuploidies and segmental aneuploidies
• Ploidy abnormalities such as haploidy and triploidy
• Contamination in the genetic material

How is PGT-A performed?

All PGT types follow the same process, which begins with an IVF cycle to create embryos. The steps are:

• Initial consultation
• Ovarian stimulation (approximately 15–20 days)
• Egg retrieval
• Fertilization of eggs with sperm (IVF)
• Embryo culture until day 5–6 (blastocyst stage)
• Biopsy of about 4–6 cells from the embryo (trophectoderm)
• Embryo vitrification (freezing)
• Chromosomal analysis (PGT-A)
• Results to identify embryos free of aneuploidy

The biopsy is a safe and simple procedure when performed by experienced professionals. It involves removing a few cells from the blastocyst’s outer layer without harming the embryo’s viability.

Who should consider PGT-A?

PGT-A is especially recommended for patients who fall into the following categories:

• Women aged 35 or older
• Patients with two or more miscarriages
• Women with two or more failed IVF cycles
• Couples with severely altered semen parameters
• Patients with previous pregnancies involving chromosomal abnormalities
• Couples carrying sex chromosome anomalies (X or Y)

IVF Genetic at IVI

Patients who need PGT-A can opt for IVI’s IVF Genetic treatment, which combines in vitro fertilization with PGT-A. This approach increases success rates and shortens the time to pregnancy.

The pregnancy rate per transfer can reach up to 70%, significantly higher than with conventional IVF. This is because embryos selected for transfer are not only the best in appearance but also chromosomally normal.

Advantages of IVF Genetic over conventional IVF:

• Higher implantation rate
• Lower miscarriage risk
• Increased chance of having a healthy baby
• Fewer IVF cycles needed to achieve pregnancy

Reproductive Genetics Unit

Understanding the key role of genetics in fertility, IVI has a dedicated Reproductive Genetics Unit offering personalized genetic counseling. This process includes:

• Review of personal and family medical history
• Construction of a family tree
• Case-specific genetic evaluation and report
• A reproductive options plan tailored to each patient

The goal is to provide comprehensive information to support informed decision-making.

Many patients can benefit from genetic counseling, making this area a cornerstone of reproductive medicine. As Dr. Pla states: “It’s impossible to imagine the future of assisted reproduction without genetics. We expect major breakthroughs, including the development of infertility gene panels, pharmacogenetics, embryo gene editing, and next-generation carrier screening.”

Other Preimplantation Genetic Tests at IVI

Besides PGT-A, IVI offers additional tests to detect different types of abnormalities.

PGT-M

This test detects genetic mutations responsible for monogenic or Mendelian disorders. It covers autosomal recessive, autosomal dominant, and X-linked diseases. Examples include cystic fibrosis, thalassemias, spinal muscular atrophy, and hemophilia.

PGT-SR

This test detects chromosomal abnormalities due to structural rearrangements such as translocations, deletions, duplications, insertions, ring chromosomes, or inversions. While carriers of structural rearrangements are usually healthy, these anomalies are a common cause of infertility.

 

Frequently Asked Questions About PGT-A at IVI

Does the biopsy harm the embryo?

Although the biopsy is an invasive technique, it does not harm the embryo when performed by trained specialists. While a small percentage of embryos may not survive the procedure, the vast majority continue to develop normally. Children born from these embryos are not at greater risk for birth defects.

How long does it take to receive results?

PGT-A results are typically delivered within seven business days.

Who should undergo PGT-A?

Any woman or couple undergoing IVF may produce aneuploid embryos. This happens even in spontaneous pregnancies. Maternal age is a key factor, so the test is especially recommended for women over 35. At that age, about one-third of embryos may be aneuploid. By age 40, that number rises to more than 75%.

Does PGT-A guarantee pregnancy?

No—but it significantly increases the chances. At IVI, the clinical pregnancy rate with PGT is 73.1%.

Can PGT-A be performed on all embryos?

Yes, once PGT-A is approved, it can be performed on all embryos that reach the blastocyst stage. This ensures the biopsy doesn’t interfere with embryo development.

What if all embryos tested are aneuploid?

In that case, the medical team will recommend not proceeding with the transfer. The team will assess the situation and offer personalized guidance on next steps.

Is PGT-A mandatory?

At IVI, all treatments are personalized. PGT-A is recommended in certain cases to maximize success, but the final decision is always made in agreement with the patient.

In summary, PGT-A is a valuable tool in assisted reproduction for patients who want to optimize their chances of a successful pregnancy. While it doesn’t guarantee pregnancy, it enables the selection of embryos with the highest potential—minimizing the risk of implantation failure or chromosomal abnormalities. Its use should always be tailored to each patient’s medical history and needs.

If you’re considering PGT-A as part of your IVF journey, talk to your medical team at IVI. They’ll guide you through the process and ensure you have all the support and information you need to make confident, informed decisions.

 

Dr Josep Pla is the Head of Reproductive Genetics at IVI RMA Global, with 8 years of experience in the field. Based in Spain, he specializes in the genetic aspects of fertility treatment, helping patients understand and navigate the role of genetics in reproductive health.

Fluent in both Spanish and English, Dr. Pla regularly works with patients from around the world, supported by IVI’s professional translation services to ensure clear, compassionate communication.

His expertise in reproductive genetics plays a key role in advancing personalized fertility care at IVI clinics globally.