The world of IVF may seem a lot like medications, procedures, doctor consultations, and so many acronyms.
But behind the scenes, there are procedures and tests like PGS and NGS that have the ability to gather all the info you need, right up to the genetic material of your future baby.
This can be pretty useful information to know right before an embryo transfer, or to find out which embryo has the most potential for a healthy pregnancy.
It’s like predicting the future, but with solid data to back it up.
So, how do these tests help?
How can knowing the genetic material of your future baby help with a healthier pregnancy?
And what do PGS and NGS even mean?
In this article: 📝
- Why do we need genetic screening?
- What is PGS?
- What is NGS?
- Who should have PGS testing?
- How accurate are PGS and NGS?
- Does PGS improve IVF success?
- How much does PGS cost?
- What are the risks of PGS?
- How long does it take to get PGS results?
Why do we need genetic screening?
Before we dive into PGS and NGS, let’s understand the need for genetic testing (or screening) in the first place.
In a nutshell, these tests check whether your embryo is genetically “normal” — that is, if it has all 46 chromosomes (genetic material) needed to grow into a healthy baby.
If there are any deviations in this number, major deletions, or abnormalities, it can result in failed implantation, pregnancy loss, biochemical pregnancies, or even babies with chromosomal syndromes.
Now, while PGS is available for patients of any age, it is often recommended for people over 35 who want to get pregnant via IVF.
This is because, as we (the source of eggs and sperm) age, there are higher chances of genetic instability in any embryos made from those sperm or eggs.
Traditionally, in IVF, embryologists always check how the embryo looks like, as a first-line indicator of its health and viability (chances of survival into pregnancy).
Divided into what are known as specific morphological parameters, if the embryo ticks all these requirements, it’s considered a “morphologically healthy” embryo.
But how embryos look isn’t always a predictor of how they are at a genetic level.
Several studies support the fact that even if there are some issues at the genetic level, an embryo may still look normal.
Here’s where PGS and NGS come in.
What is PGS?
Pre-implantation genetic screening (PGS) is a genetic screening test that detects any abnormalities in the embryos at the genetic level.
It does this by screening the chromosomes of the cells of the embryo.
Here’s how the procedure goes:
- In an IVF cycle, embryos are formed when eggs are fertilized with sperm
- A few cells are obtained from the embryo, via a procedure known as biopsy
- This genetic material of the embryo is then sent to the genetic lab for analysis
- The analysis reports if there are any abnormalities in the embryo, or if it is fit for transfer into the uterus
What is NGS?
Next-generation sequencing (NGS) is an advanced technology used for PGT (pre-implantation genetic testing) that allows advanced detection of abnormalities in the genetic material of the embryos.
So, basically, like a super-powered PGS.
It’s a relatively new technology that, so far, has been used to detect:
- Aneuplodies (genetic defects) in embryos
- Single chromosomal disorders
- Genetic material relocation/translocation within chromosomes
This is also promising for the future of IVF, since methods of analyzing genetic material without disturbing the growing embryo are currently in development.
In IVF, embryos are grown in tiny glass dishes with culture medium (nutrients to help the embryo grow).
According to sources, with NGS, it is possible to take this culture medium out and analyze it for the genetic material of the embryo — all without disturbing the embryo itself.
What’s the difference between NGS and PGS/PGT?
Pre-implantation Genetic Screening (PGS), is the procedure that aims to provide an overview of the chromosomal condition of the embryos.
This predicts if the embryos are euploid (genetically normal) or aneuploid (genetically abnormal).
On the other hand, Next Generation Sequencing (NGS) is the procedure or the technology behind PGS that enables it to perform complex and detailed procedures like identifying a single gene disorder, any translocation of genetic material, and so on.
Who should have PGS testing?
A PGS test is often recommended for:
- People who are over 35 years old
- Those who have experienced recurrent (repeated) implantation failure
- Those who have experienced recurrent pregnancy losses
- Those who have any known inheritable disorders in their family tree
- Donor embryos (if requested)
Is PGS testing necessary for IVF?
No, PGS testing is not a routine procedure for IVF.
But it may be recommended to those who could benefit from the test.
If you’re unsure whether PGS testing would be right for you and your IVF journey, have a chat with your doctor.
How accurate are PGS and NGS?
PGS for normal or abnormal embryo detection has an accuracy rate of 95%.
The rate of possible misdiagnosis stands at 5% for each embryo.
However, in tests where NGS is combined with PGS for specific tests, the accuracy is greater than 99.94%.
So, yeah, they’re pretty accurate.
Does PGS improve IVF success?
Usually, yes, PGS improves IVF success rates, since it means doctors can select the most viable embryo with the best chance at becoming a healthy pregnancy.
Studies also suggest that PGS can not only increase the pregnancy success rate, but also reduce anxiety surrounding chances of stillbirth or fetal abnormalities.
How many embryos make it through PGS?
Around 60-70% of embryos are generally said to make it through PGS.
So if you were to go through a cycle, retrieve eggs, create embryos, and send them for testing, at least one would be genetically normal to transfer.
But this percentage varies depending on your age, being higher if you’re under 35, and gradually decreasing until the age of 42 and older.
Does PGS testing increase the chance of twins?
No, PGS testing alone doesn’t increase the chance of twins.
Basically, if two embryos are transferred to your uterus post-PGS testing, there’s a higher chance of twins.
You can also elect to have a single, PGS-tested embryo transferred to your uterus, which definitely won’t result in twins.
How much does PGS cost?
On average, the cost of PGS is around a minimum of £10,000 per cycle in the UK or $10,000-$30,000 in the US.
The cost of PGS varies because of the pricing structure of the clinic, as well as the number of embryos that go into the PGS cycle.
There are additional costs for each extra embryo that goes into a PGS cycle.
Some clinics may also offer a fixed price for a specific number of embryos.
What are the risks of PGS?
While PGS itself is a standardized procedure in the field of IVF, each embryo and each case is unique on its own.
During PGS, the embryos may be slightly damaged due to the removal of cells that take place.
There’s also a chance it may not survive the warming process, if it’s frozen after the PGS process.
This is why there are several studies that suggest that PGS isn’t carried out as a routine procedure, but instead limited to specific IVF patients.
How long does it take to get PGS results?
It typically takes anywhere between 10-12 days to get PGS results.
This also varies depending on your chosen clinic and the genetic lab they use to carry out the actual testing.
So you shouldn’t have too long to wait to get the results.
Ultimately, IVF can be a process that requires time, hope, and effort from you.
At times, it may seem like you’re learning new terms and navigating a new challenge each time you step into the clinic.
But we’re here for you, every step of the way.
And if you want to connect with other moms and moms-to-be who get it, join the conversation on Peanut.
You’re not alone in this.