PGTA

The path to healthy embryos

Preimplantation Genetic Testing for Aneuploidy (PGT-A) is a revolutionary technique in the field of assisted reproductive technology (ART) that offers valuable insights into the genetic health of embryos before they are transferred during in vitro fertilization (IVF).

  • The initial cell of an embryo consists of chromosomes inherited from both the sperm and the egg. If this cell does not possess the correct number of chromosomes, it can result in failed implantation or miscarriage. With the aid of Preimplantation Genetic Testing for Aneuploidy (PGT-A), we are able to examine the cells of an embryo to ensure they have the appropriate number of chromosomes prior to transferring them to the uterus.

  • By utilizing PGT-A, the embryologists can achieve a remarkable success rate of up to 98% in identifying embryos with chromosomal abnormalities before the transfer procedure. This process of selecting healthy embryos can significantly enhance the success rates of in vitro fertilization (IVF) while simultaneously reducing the risks associated with multiple pregnancies and the chances of miscarriage.

THE PROS & CONS

    1. Enhanced Embryo Selection: PGT-A allows for the identification of embryos with the correct number of chromosomes, reducing the likelihood of implantation failure and miscarriages.

    2. Increased Pregnancy Rates: By selecting chromosomally normal embryos, the chances of achieving a successful pregnancy are improved, particularly for individuals or couples with a history of infertility or recurrent pregnancy loss.

    3. Reduced Risk of Genetic Disorders: PGT-A can identify embryos carrying chromosomal abnormalities, including those associated with conditions such as Down syndrome, Turner syndrome, or other genetic disorders, enabling informed decisions regarding embryo selection.

    1. False Positive or False Negative Results: PGT-A is highly accurate but not infallible. There is a small risk of misdiagnosis due to technical limitations or mosaicism (presence of both normal and abnormal cells in the embryo).

    2. Limited Genetic Screening: PGT-A only screens for aneuploidy (abnormal number of chromosomes) and does not provide comprehensive testing for all genetic conditions or mutations.

    3. Cost and Additional Procedures: PGT-A involves additional costs for embryo biopsy, genetic analysis, and embryo freezing. It also requires the expertise of a skilled fertility clinic and specialized laboratory.

THE PROCESS

  • The patient undergoes ovarian stimulation to produce multiple eggs, which are retrieved through a minimally invasive procedure.

  • The retrieved eggs are fertilized with sperm in the laboratory, resulting in the formation of embryos.

  • A few cells are gently removed from each embryo for genetic analysis, while the embryos are kept in a controlled environment.

  • The extracted cells undergo genetic testing to assess the number of chromosomes present in each embryo.

  • Chromosomally normal embryos are selected for transfer into the woman's uterus during a carefully timed procedure, increasing the chances of a successful pregnancy.

  • PGT-A is primarily recommended for individuals or couples with specific indications, such as advanced maternal age, a history of recurrent pregnancy loss, or previous unsuccessful IVF cycles.

  • While PGT-A increases the likelihood of selecting chromosomally normal embryos, it does not guarantee a successful pregnancy. Other factors, such as the woman's overall health and uterine receptivity, also contribute to pregnancy outcomes.

  • In a significant RCT called the STAR trial, published in December 2019, it was observed a significant increase in pregnancy rates among a specific subset of women aged 35-40 with more than two embryos available for testing. However, across all age groups, there was no overall increase in ongoing pregnancy rates. Nonetheless, it is acknowledged that further robust clinical and laboratory trials are necessary to determine whether PGT-A significantly enhances live birth rates.

    Embryo biopsy is a delicate procedure, but in the hands of experienced embryologists, the risk of harm to the embryo is minimal.

  • With PGT-A, each embryo will have one of four results:

    • Euploid: This refers to embryos that have a balanced genetic composition with 46 chromosomes. These embryos are suitable for transfer during fertility treatment.

    • Aneuploid: These embryos have an unbalanced genetic makeup, with an abnormal number of chromosomes, either too few or too many. Due to the higher risk of failed treatment or miscarriage, we do not transfer these embryos.

    • Mosaic: Some embryos exhibit a mosaic pattern, meaning they have a mix of both normal and abnormal cells. The biopsy procedure may capture cells that are either all normal or all abnormal. Mosaic embryos, which account for less than 9% of cases, can present challenges in interpreting PGT-A results accurately, potentially leading to false positive or false negative outcomes.

    • No result: In rare cases, representing less than 5%, it may be challenging to determine whether the embryo is euploid or aneuploid. In such instances, these embryos can still be considered for transfer or, under special circumstances, they might undergo re-biopsy to obtain a more conclusive result.

PGT-A is a powerful tool that aids in the selection of chromosomally normal embryos, thereby increasing the chances of a successful pregnancy while reducing the risk of certain genetic conditions. Understanding the benefits, risks, and process of PGT-A is crucial for individuals or couples considering assisted reproductive techniques. Consulting with an experienced fertility specialist like Dr Kleanthis can provide individuals with personalized guidance and support.

Book your non-obligatory discovery call today to see if PGT-A is suitable or indicated in your case, to ensure the best possible chance of achieving your dream of having a child.