What is PGS?


Based on information obtained from large-scale studies, in general, about 50% of human embryos are chromosomally abnormal before implantation through IVF. However, this rate is minimized for those who have IVF in Iran. As you can see in the chart below, the number of abnormalities is largely influenced by women and is proportional to their age. The chromosomes of the eggs of older women have a much more significant abnormality.

Fertility specialists offer a solution for this group of people who may face the problem of abnormal chromosomes, which is called PGS. Preimplantation Genetic Screening (PGS) refers to the removal of one or more cells from an IVF embryo to test for chromosomal normality. As you know, humans naturally have 23 pairs of chromosomes, making a total of 46 chromosomes. The presence of an extra chromosome or the absence of a chromosome less than 46 chromosomes will cause genetic abnormalities and this is where PGS comes in to test and screen the embryo for normal chromosome number.

For example, Down syndrome patients have an extra copy of chromosome number 21, which can be detected by PGS before birth. Of course, PGS is not applicable for specific diseases such as cystic fibrosis or hereditary diseases, and these types of diagnoses will be the responsibility of PGD; Preimplantation Genetic Diagnosis. In the following, you will read everything about PGS, how it works with IVF in Iran, costs and risks, etc.





How Is PGS Testing Done?

If you read anywhere or hear from anyone about doing the PGS process, you may come across different classifications and designations. But we have categorized the steps of doing PGS into 8 steps so that you can get a good understanding of what is ahead of you.


Step 1 – Ovarian Stimulation

The first step in this process is the stimulation of the ovaries, which is done using hormonal injections to produce multiple eggs. This injection usually starts on the second day of the period after the basic ultrasound and should be done daily for about 10 to 12 days. During these 10 to 12 days, an ultrasound is performed every 3 to 4 days to monitor the response. In the end, just when the follicles have found a suitable size, the doctor plans a trigger injection.


Step 2 – Collection of Eggs

In the next step, the eggs are retrieved and this happens under anesthesia in the operating room and with the help of ultrasound. After the eggs are retrieved, the embryologist obtains and checks the total number and the number of mature ones.


Step 3 – Insemination

After retrieval, the eggs are fertilized in 2 ways.

  • In Vitro Fertilization (IVF) – Sperm and egg are placed in a culture dish and fertilization occurs completely naturally.
  • Intracytoplasmic Sperm Injection (ICSI) – The Specialist will directly inject a single sperm into a mature egg.


Step 4 – Embryo Culture

Under specific culture conditions, the embryos grow to the blastocyst stage, i.e., on the fifth or sixth day in the laboratory. During this time, the embryologist examines the embryo and its development every day at the times he has determined in advance.


Step 5 – Embryo Biopsy

When the embryos reach the blastocyst stage, the embryologist performs a multi-cell biopsy for testing. Due to the highly specialized and technical nature of embryo biopsy, this procedure can only be performed by highly trained and accredited embryologists.


Step 6 -Checking for Abnormalities

After performing a biopsy, the specialist will send the material to the genetic testing laboratory for PGS.


Step 7 – Embryo Transfer

After the genetic testing laboratory determines the PGS result, embryos with a normal karyotype are selected for transfer to the uterus. The point is that in order to avoid the possibility of higher-order multiple pregnancies, the specialist transfers only one or two embryos to the uterus at a time. The specialist also freezes other normal and healthy embryos for future use.


For more information, Read:

What is embryo transfer?


Step 8 – Pregnancy Test

Finally, 14 days after embryo transfer, a pregnancy test is performed.


PGS Testing Time Duration

For each test, there is a series of actions before, a series of actions during, and a series of actions after the test. The total amount of time that each of these actions requires depends on various factors. PGS is no exception to this rule. But the PGS test results will be available independently within 7-10 days.


Best Candidates For PGS

Anyone undergoing IVF in Iran can opt for the PGS test. However, infertility treatment specialists recommend PGS testing for some patients more than others.

  • Older women are more likely to ovulate with chromosomal abnormalities.
  • Women who have had multiple failed pregnancies, multiple miscarriages, or multiple failed IVF cycles – PGS can generally identify problems that caused previous IVF cycles or pregnancies to fail.
  • And especially for those who have had a known pregnancy with an embryo with a chromosomal abnormality – PGS has the ability to ascertain whether or not there is a chromosomal abnormality in an embryo transfer.


Benefits Of PGS

One of the most important things that PGS does is to show whether the embryo has the right number of chromosomes. It can also:

Significantly reduce the risk of pregnancy with an abnormal embryo that occurs in women conceived through natural or IVF, at any age, and often leads to miscarriage or treatment failure.

PGS also helps you get a positive pregnancy test result in the least number of IVF cycles.

Another plus point of PGS is that it helps you avoid failure in future IVF cycles and pregnancies – if the PGS results show that you only have abnormal embryos, you can consider alternative ways such as using donor sperm and donor eggs to have a successful pregnancy.


Risks Of PGS

Infertility doctors and specialists believe that PGS is a very safe procedure with a risk of harming the embryo during cell extraction of less than 1%.

This safety is because embryologists trained in cell extraction techniques and precise genetic test processing methods and qualified embryo biopsy specialists perform PGS only on embryos that have reached the day fifth blastocyst stage.

Although this statement is not considered one of the risks of PGS, you should keep in mind that the accuracy rate of PGS is 97%, which means that the risk of pregnancy affected by chromosomal abnormalities is not completely eliminated. So, in addition to PGS, the patient must also perform the tests prescribed by the doctor.


PGS Success Rate

In reply to the question that patients who are having IVF in Iran ask fertility specialists about the success rate of PGS, it is said that normal PGS embryos have a success rate of about 60-70%. But this is on a per-transfer basis. This means that if you start a cycle, retrieve the eggs, produce an embryo, and do the PGS test, resulting in an embryo returning to normal, it will result in a live birth 60-70% of the time.




Best Place For PGS

When the speaking of the best place for PGS comes along, you start to think about pricing, quality, the equipment. IVF in Iran is very popular and there are a lot of reasons. Factors such as reasonable prices, the highest quality, and the most advanced equipment are some of the reasons that IVF in Iran is very popular. Besides, to have a safe and easy journey along with your treatment, you can come with a facilitator from your targeted country. Now in here, if you decide to have PGS along with your IVF in Iran, the best labs and hospitals are in participating with CarefulTrip health tourism agency to bring you the best results. All you need is to contact our consultants to begin your journey.

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