What is PGS testing and Should I Consider It?
If you know you need in vitro fertilization (IVF), you might want to speak to your doctor about whether or not you should consider using PGS testing, which stands for Preimplantation Genetic Screening. PGS testing is a genetic study of the embryos produced during your IVF cycle which has a goal of helping you have a successful pregnancy and a healthy baby.
In late 2018, several top reproductive entities such as the American Society of Reproductive Medicine, The European Society of Human Reproduction and Embryology and The International Committee Monitoring Assisted Reproductive Technologies decided to change the name of PGS Testing. Since PGS looks for aneuploidies, which is the presence of an abnormal number of chromosomes in an embryo, going forward, PGS Testing will be called Preimplantation Genetic Testing for Aneuploidies (PGT-A).
What does PGS testing Entail?
PGS testing screens your embryos for any chromosomal abnormalities before transferring the embryo into your uterus. If you and your doctor feel you could benefit from this test, it fits easily into your routine IVF treatment.
The cycle would start as usual, with ovarian stimulation and monitoring. Your eggs would be retrieved and fertilized in the IVF lab. Then, after fertilization, an embryo biopsy is taken at typically day five or six of the embryo’s development, meaning that a few cells from the embryo are extracted and analyzed. Each cell should contain 23 pairs of chromosomes, or 46 chromosomes total. PGS testing assesses all 23 pairs of chromosomes, including the two sex chromosomes (X and Y) that determine the embryo’s sex. PGS testing can test to see if there are any extra or missing copies of chromosomes in each embryo.
A small sample of each embryo is sent to a genetic testing lab, but your embryos will safely be stored at your IVF clinic. Once the PGS testing is complete, results are sent back to your doctor, which can help identify which embryos should be transferred back to the uterus.
Who Should Consider It?
Overall, PGS helps to determine whether or not embryos appear to have the correct number of chromosomes. This is something many patients could benefit from, as it can increase pregnancy rates per transfer and reduce the risk of miscarriage, but it’s particularly recommended for the following:
- If you’re over the age of 35 years old: The American College of Obstetricians and Gynecologists have indicated that women over the age of 35 have a higher propensity for disorders that impair fertility and miscarriages. In addition, as women age, the chance for chromosomal abnormalities in embryos increases. PGS testing can be incredibly helpful for these patients by testing for chromosomal abnormalities in embryos prior to transfer.
- If you’ve experienced more than two miscarriages: PGS testing is known to reduce miscarriage rates by testing for chromosomal abnormalities in embryos prior to transfer. This is because around half of all miscarriages are due to chromosomal abnormalities. In addition, you could speak with your doctor about Products Of Conception (POC) testing, which is done on tissue from the lost pregnancy and evaluates the chromosomes to help provide insight into what has caused the miscarriage.
- If you’ve had multiple rounds of IVF that were not successful: PGS testing is known to increase the likelihood of a successful embryo transfer by identifying which embryos appear chromosomally normal. In turn, this may help eliminate the need for as many cycles of IVF.
Ultimately, deciding if PGS testing is important or beneficial to your next IVF cycle is a conversation for you and your doctor to have. The ideal goal is for you to be well-informed about the options available to you so you can speak to your partner and reproductive endocrinologist about what you feel comfortable with and what will give you the best chance of a happy, healthy pregnancy.