Preimplantation Genetic Screening (PGS)

For intended parents who opted for in vitro fertilization (IVF) to carry a pregnancy to term, embryo transfer is the long-awaited final step of this journey. Now let us introduce you to Preimplantation Genetic Screening.

As an intended parent, you can screen your embryos before the procedure of embryo transfer through a technique known as preimplantation genetic screening (PGS), also known as preimplantation genetic testing for aneuploidies (PGT-A)

PGS/PGT-A is a rapidly evolving ART technique that has been proved to be beneficial for many. When pursuing IVF, it is important to talk to your fertility doctor about what’s best for you. 

What is PGS/PGT-A? 

PGS/PGT-A is the process of identifying each selected embryo’s number of chromosomes present. Abnormal chromosome numbers, also known as aneuploidy, are a significant source of challenge in pregnancy and birth. A normal embryo has 46 chromosomes; any more or less than 46 chromosomes can significantly impact your chances of conceiving and can come with consequences if the embryo is carried to term. 

PGS/PGT-A Process During IVF

By performing PGS/PGT-A, your fertility doctor can ensure that the embryos selected for the transfer have a healthy number of chromosomes to prevent abnormalities that will impact the pregnancy. When an embryo has an abnormal number of chromosomes, it can prevent implantation, cause pregnancy loss, or create significant health problems in your baby, which can be very difficult for intended parents undergoing IVF. 

Benefits of PGS/PGT-A

1. Improved embryo selection 

The goal of PGS is to increase the likelihood that your selected embryo(s) will lead to a successful, healthy conception for your future family. PGS testing reduces the risk of miscarriage, decreases the time it takes to become pregnant and lowers the need for transferring multiple embryos. While there is often additional cost to perform PGS, it can often decrease the price of your IVF journey in the long run by decreasing the number of transfers necessary to conceive. 

2. Gender Selection (if desired)

Also known as Family Balancing or Family Planning, you can use PGS/PGT-A to see each embryo’s sex chromosomes and transfer the embryo(s) of their desired gender. 

Reasons for gender selection may include: 

  • You’re more equipped to raise one gender over another
  • You have one or more children of the opposite sex, and would like to have a balanced family
  • You experienced a devastating loss of a child and hope to raise another of the same gender 
  • You and your partner would like to mitigate the risk of passing down genetic diseases found in one gender more than another

Each intended parent faces different circumstances, and selecting your child’s gender is a deeply personal reason. Your fertility clinic will cover this in more depth regarding your unique scenario and should always respect your decision. 

3. Prevent genetic transmission of unknown abnormalities 

PGS/PGT-A doesn’t test for specific diseases but instead looks for chromosomal abnormalities, such as the number and position. By performing PGS/PGT-A on your viable embryos, your fertility doctor can select chromosomally normal embryos and rule out those that would prevent a healthy birth, even if they appear high-quality before screenings. 

However, if one or both intended parents have a known genetic disorder such as cystic fibrosis, preimplantation genetic diagnosis (PGD) is a better option for you. 

4. Optimized chance of a successful pregnancy

PGS gives your fertility doctors insight into which embryos will be most likely to implant and develop healthily. If your embryos display specific abnormalities that prevent the transferred embryo from implanting within the uterus or developing during its early stages, your doctor can identify and abstain from transferring these embryos to optimize your IVF process. 

Still, some chromosomal abnormalities are less harmful to the embryo and allow it to implant. These can still prevent pregnancy from developing correctly and can lead to pregnancy loss or a child’s birth after the embryo transfer. 

5. Quicker time to pregnancy 

Using PGS/PGT-A, your fertility clinic can avoid unsuccessful embryo transfers by transferring the healthiest embryos first. By understanding which embryos will help you achieve a full-term pregnancy, you can ensure you’re not spending months transferring embryos that won’t lead to a successful pregnancy and birth.

6. Reduced monetary burden

PGS testing is sometimes an additional expense, depending on your provider and payment options. Still, the procedure gives you insight into which embryos are worth transferring and freezing. Even with the additional cost of PGS/PGT-A, there’s a long-term payoff from understanding which embryos are viable for storage and which embryos are worth transferring during IVF. 

7. Less uncertainty 

A significant benefit of PGS/PGT-A is the reduced level of uncertainty patients may experience before and after the embryo transfer. PGS provides you with an ensured healthy embryo, a lower risk of pregnancy loss, and less emotional stress, especially for patients who’ve experienced the saddening loss of miscarriage before.

8. Identify fertility treatment options

When undergoing PGS, you should prepare for the possibility of genetically flawed embryos, meaning that your fertility doctor can’t transfer them to the uterus. As heartbreaking as this is, your doctors will walk you through your best plan of action and get you back on track for a successful, healthy conception and pregnancy. 

If you are facing infertility and looking for the best fertility treatment centre to help you, Ekmi Fertility is the right place. You can reach out to us by calling +91-7011-587-880 or email us at


What does preimplantation genetic screening test for?

Preimplantation genetic diagnosis can test for over 400 different single-gene disorders, including cystic fibrosis, sickle cell anemia, Tay-Sachs, and Huntington’s disease. PGD can test for both disorders that would be fatal to the fetus or baby as well as illnesses that may not affect children until they are older.

How is preimplantation genetic screening done?

How is the screening performed? During an IVF cycle, patient’s embryos are assessed for biopsy on days 5 or 6. During biopsy a single cell or cells are removed from the embryo. Following the embryo biopsy, embryos are cryopreserved and the testing is performed on the biopsied cell(s).

What is the difference between PGS and PGD?

PGS analyzes biopsied cells from the embryo to screen for potential genetic abnormalities when there are no known potentially inherited disorders. PGD, on the other hand, uses the same process to detect a specific disorder that has a high probability of being passed down from parents to their offspring.

How accurate is preimplantation genetic screening?

What is the accuracy of PGD? Overall PGD is able to diagnose genetic defects with approximately 98% accuracy. Even if a patient undergoes PGD, prenatal testing such as amniocentesis and chorionic villus sampling (CVS) is usually recommended to confirm the PGD diagnosis.

Does PGS reduce miscarriage?

After PGS, the miscarriage rate was reduced from the previous 90% (expected 29%) to 23% in the women at age <35 years, and from 86% (expected 44.5%) to 12% in the women at age ≥35 years.