In vitro fertilization (IVF) is a profound journey for many couples, but one often filled with challenges and uncertainty. Human and cell biology is complicated, and it’s not uncommon for IVF patients to experience miscarriage or fetal development abnormalities due to chromosomal issues in the embryo.
With advancements in medical technology, "embryo chromosome testing" (PGS/PGT-A) has brought renewed hope to many families. But what exactly is PGS and PGT-A? Are they the same or different? Are they necessary? How much do these tests cost?
Today, we’ll examine PGS and, more specifically, PGT-A to understand how these tests can enhance embryo implantation and pregnancy rates.
1. Introduction to PGS (PGT-A):
2. Differences Between Third-Generation IVF Technologies:
3. Necessity and Applicability of PGS (PGT-A):
4. Understanding the PGS (PGT-A) Testing Process
5. PGS (PGT-A) Costs to Patient
6. Advantages and Disadvantages of PGS (PGT-A)
PGS, now often called PGT-A (Preimplantation Genetic Testing for Aneuploidies), is typically used in in vitro fertilization (IVF) treatments. It helps determine whether the number of chromosomes in an embryo is normal before embryo transfer and implantation into the uterus. Normal human cells have 23 pairs of chromosomes. Abnormalities in the number of chromosomes can lead to failed implantation or chromosomal disorders, such as Down syndrome. A major clinical study was conducted recently (Fertility & Sterility, March 2021) showed that chromosomal abnormalities significantly reduce implantation success rates, pregnancy rates, and live birth rates.
The following diagram compares the information provided by traditional PGS (PGT-A), PGD (PGT-M), and PGT-SR:
Although conventional PGS (PGT-A) provides valuable information, it is unable to identify the chromosomal ploidy status of embryos, those with triploid or haploid issues. This is an important limitation of traditional PGS (PGT-A), but the new generation test, Embryo46, can solve this problem with ploidy status detection.
Differences Between PGT-A and PGT-M Technologies What is the difference between PGS (PGT-A) and PGD (PGT-M)? When do couple need to consider PGT-M? Althought these two terms sound similar, we’ve compared them on the table below to helpyou quickly understand the differences:
| Testing Method | PGS/PGT-A (Preimplantation Genetic Screening) | PGD/PGT-M (Preimplantation Genetic Diagnosis) |
|---|---|---|
| Testing Purpose | Screening embryos for chromosomal number or structural abnormalities | Screening embryos for specific single-gene genetic diseases |
| Applicable Diseases | Chromosomal number abnormalities such as Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), etc. | Single-gene diseases such as thalassemia, cystic fibrosis, Huntington's disease, etc |
| Suitable Candidates | Older women, couples with recurrent miscarriages, or those wishing to increase the success rate of IVF treatments | Parents with a family history of genetic diseases or known carriers of single-gene genetic diseases |
| Scope of Application | Screening the entire genome of the embryo for chromosomal number and structure, but cannot detect small chromosomal fragments and single-gene abnormalities | Detecting specific gene mutations, focusing on known single-gene genetic abnormalities |
According to the American Society for Reproductive Medicine, using PGS (PGT-A) is associated with higher implantation rates and lower miscarriage rates across all ages, especially in older (35+) age groups. The following chart shows statistics by age group:
Other the other hand, a retrospective study by Beth Israel Deaconess Medical Center, affiliated with Harvard Medical School (Human Reproduction, October 2020), highlighted the practical significance of PGS (PGT-A) ONLY for older patients:
PGS (PGT-A) is applicable to range of groups, not just older patients:
Women aged 35 years or above
History of multiple failed implantations
Repeated miscarriage
Previous pregnancy or birth of a fetus with chromosomal abnormalities
One spouse with a chromosomal abnormality (e.g., chromosome translocation, fragment defect)
A Japanese clinical study (Human Reproduction, December 2019) investigated patients with recurrent implantation failure and miscarriage. Although the study had a small sample size, it found that PGS (PGT-A) can indeed improve success rates in these group of patients.\
Each treatment and family planning scenario is unique, so if you are considering PGS (PGT-A), it’s important to fully discuss it with your doctor before making a decision.
The cost of PGS testing for a single embryo ranges from approximately USD $500 to $1,500, varying by institution. These costs typically include embryo biopsies, freezing reagents, and testing. If multiple egg retrievals or embryo cultures are required, the costs will accumulate. How many embryos should be tested for PGS (PGT-A)? Ideally, the more normal embryos, the better. For patients over 42 years old, the proportion of genetically normal embryos may be only about 10%, meaning at least 10 embryos are needed to ensure a normal embryo for subsequent implantation.
For other indications, such as recurrent miscarriage or genetic abnormalities, the number of embryosrequired will vary. Generally, 6 to 12 embryos are recommended to ensure obtaining normal embryo for transfer. Other factors to consider include embryo quality, judged by morphology. Even with many embryos, if the quality is not medium or high, the success rate of implanting low-quality embryos remains low, even with PGS (PGT-A) testing. Some patients may have only a small number of embryos, even less than 3. Therefore, it is recommended to consult with your doctor to understand how many embryos need to be tested and the associated costs.
Understanding the PGS (PGT-A) Testing Process
Chromosome testing may sound complicated, but the PGS (PGT-A) process is straightforward, divided into several steps:
1. Embryo Biopsy: A small number of cells are taken from the embryo.
2. Chromosome Analysis: The cells are analyzed for chromosomal abnormalities using NextGeneration Sequencing (NGS).
3. Report Generation: A report is generated, typically within 7-14 working days
After the report is produced, the doctor will discuss the results with the prospective mother and choose the embryo(s) to be implanted. PGS (PGT-A) reports typically show three types of results:
• Euploid Embryos: Chromosomally normal embryos suitable for implantation.
• Aneuploid Embryos: Embryos with abnormal chromosome numbers, not suitable for implantation.
• Mosaic Embryos: Embryos composed of cells with both normal and abnormal chromosome numbers. Mosaic embryos may have a reduced chance of implantation and pregnancy but can sometimes correct themselves to form a normal embryo. However, mosaic results couldbe false positive due to NGS’s limitation.
• Improves implantation and pregnancy rates, which would then
• reduces the costs and emotional burden of implanting aneuploid embryos
• Decreases the need for multiple embryo transfers, reducing medical risks and burdens from multiple births
• Cost
• All embryos tested are aneuploid, resulting in no transferrable embryos
• False positive results
In addition to PGS (PGT-A) and PGT-M, more diverse and comprehensive testing methods are under development. Inti Labs and our Embryo46 have major advantages:
Top Team and Advanced Technology:
Led by an internationally renowned former-Stanford professor who started the one of the first PGS testing services.
Mostre Comprehensive Chromosome Testing:
Embryo46 dDetects chromosomal number chromosomal fragment abnormalities, challenging chromosomal ploidy status.
Perfect Specimen Transportation and Preservation:
Fully controlled low-temperature shipment during transportation.
Rigorous Laboratory Quality Control:
Certified by the College of American Pathologists (CAP), with a dual-person review system to ensure accuracy and reliability.
At Inti Labs, we understand the emotional and physical journey that couples undergo in their quest to start or grow their families. Our commitment to providing cutting-edge technology and compassionate care aims to make this journey as smooth and hopeful as possible.
With our advanced Embryo46 testing, we’re able to offer the best chances for a successful pregnancy by ensuring the highest standards of accuracy and reliability. If you have any questions or need further information, please don't hesitate to reach out to our dedicated team.
