Understanding The Role of PGT-A in Your IVF Journey

There's probably a whirlwind of questions in your mind when you decide to start your IVF journey. As you research IVF, one term you've likely encountered is Preimplantation Genetic Testing or PGT. This is a form of genetic testing that looks at the health of embryos produced during IVF by screening the embryos' genetic anomalies and finding those with the highest chance of leading to a healthy pregnancy.

One common PGT you will come across again and again is Preimplantation Genetic Testing for Aneuploidy, more simply known as PGT-A. But what exactly is PGT-A, and how does it fit into your fertility journey?

What is PGT-A and How Does It Work?

PGT-A (previously known as preimplantation genetic screening or PGS) is a testing method designed to help your fertility team select embryos with the correct number of chromosomes, so as to improve your chances of a successful pregnancy and birth. 

Chromosomes are essential in pregnancy and childbirth, guiding how your baby develops. A normal embryo contains 46 chromosomes, 23 inherited from each parent. Having all 46 chromosomes usually results in a healthy pregnancy and live birth. 

What Are Chromosomes?

Before we discuss how PGT-A works, it’s important to understand chromosomes. Chromosomes are structures that look like thread found within cells. They are made of protein and a single molecule of DNA carries the genomic information from cell to cell. 

Humans have 22 pairs of chromosomes (autosomes) and one pair of sex chromosomes (XX or XY), for a total of 46. Each pair has two chromosomes, one from each parent. This means that children inherit half of their chromosomes from their mother and half from their father. 

Usually, the embryo has all 46 chromosomes. Such embryos are known as euploid embryos and they have a good chance of healthy development and growth. 

On the other hand, aneuploid embryos are embryos with either fewer or more chromosomes. These embryos can lead to unsuccessful implantation, miscarriage, developmental problems, or genetic disorders. The most common type of aneuploid embryo disorder is Trisomy 21, or Down Syndrome. This syndrome happens when the embryo has an extra chromosome 21. 

In some cases, the embryo has both euploid and aneuploid cells. Such embryos are known as mosaic embryos. 

PGT-A then becomes a great resource for identifying aneuploid embryos in order to avoid transferring them during an IVF cycle. 

How PGT-A Works

During PGT-A, about 4-5 cells from a 100-150 cell embryo are gently removed and tested to assess the number of chromosomes within. The results from the biopsy help Ivy Fertility know how chromosomally healthy the embryo is. 

In the case of mosaic embryos, the fertility specialist looks at the proportion of euploid and aneuploid cells to determine how successful or unsuccessful a pregnancy will be. 

Each fertility clinic has its own practices, and some discard the mosaic embryos if there’s still a fear that the PGT-A analysis has shown aneuploid cells. Nevertheless, there are reports of healthy live births even after a transfer of a mosaic embryo, and it’s important to discuss this with your clinic. Your clinic might advocate for this while another facility might choose not to. 

Extensive research on PGT-A shows that, while your overall chance of delivering a baby from one full IVF cycle (cumulative live birth rates) appear quite similar whether you use PGT-A or not, the difference emerges when you look closer at individual embryo transfers.

With PGT-A, your fertility doctor can prioritize the transfer of only chromosomally normal embryos, leading to increased success per embryo transfer and a reduced risk of miscarriage. Considering nearly half of first-trimester miscarriages stem from chromosome issues, this is particularly reassuring for anyone who’s experienced pregnancy loss.

Is PGT-A Right for Everyone?

The question on your mind might be “How do I know I need PGT-A?”. Interestingly, the American Society for Reproductive Medicine (ASRM) guidelines for 2024 state clearly that PGT-A is not universally recommended for every IVF patient. This is because IVF journeys are uniquely personal. Each is shaped by different goals and medical histories.

Miscarriage Prevention

For couples who've endured the emotional and physical challenges of recurrent pregnancy loss (RPL), PGT-A can feel like a lifeline. Over the years, studies show that chromosome abnormalities account for 50% of first-trimester miscarriages. 

If you've faced multiple miscarriages or you're nearing a later stage of reproductive age, PGT-A may significantly reduce the risk of future miscarriages by allowing your fertility team to choose embryos more likely to succeed. However, PGT-A may not drastically change the overall cumulative success rates for every IVF patient. 

If miscarriage has been a painful part of your fertility story, discussing PGT-A with your fertility specialist could open new avenues of hope and reassurance.

Safety and Risks: Should You Worry?

Naturally, any procedure involving embryos brings understandable anxiety, and many patients wonder whether PGT-A could potentially damage the embryos retrieved during an IVF cycle. Though the process sounds intimidating, the procedure (a biopsy) used to get the cells is generally safe, carrying only a minimal risk of around 1-5%. This risk is sometimes linked to the embryo's initial quality.

Additionally, embryos tested with PGT-A are usually frozen and thawed for later transfer. The thawing process itself comes with a small chance that an embryo won't survive. But, thankfully, these occurrences are rare. Discussing these nuances openly with your fertility clinic ensures transparency, clarity, and confidence in your treatment decisions.

Aligning PGT-A With Your Goals

Ultimately, your decision about incorporating PGT-A into your IVF journey should align deeply with your personal fertility goals. Whether your motivation is reducing miscarriage risk, considering family balancing, preserving fertility, or maximizing every transfer's success, your choice should reflect your values and situation.

Remember, it's perfectly valid to take the time to have a thorough discussion with your fertility specialist or a licensed genetic counselor. Each of your questions and concerns deserves thoughtful attention and individualized answers.

Your Next Steps

Embarking on IVF and deciding whether PGT-A is right for you can be challenging. The questions might feel endless, and the uncertainty overwhelming. But this also has the potential to be empowering. Knowing you're making informed choices is a powerful first step toward peace of mind, and this can allow you to choose your own path.

As you take your next steps, talk with your fertility care team and ask all the questions you have. Have an open mind that while PGT is highly accurate, it cannot detect every possible genetic anomaly, and your fertility doctor may recommend additional prenatal testing to help identify any health concerns early.