About 70% of all failed pregnancies (implantations) are due to chromosomal abnormalities in the fertilised egg (embryo). Pre-Implantation Genetic Diagnosis (PGD) and Pre-Implantation Genetic Screening (PGS) are used to identify which embryos are most likely to result in a healthy pregnancy before they are implanted in the uterus.
PGS tests for the presence of any extra or missing whole chromosomes compared to the normal set of 23. PGS works by taking a few cells from each embryo and testing these cells (biopsy).
In the past, the fluorescence in situ hybridisation (FISH) method of PGS was more widely used. This method tests for abnormalities in chromosomes including 21, 18, 13, X and Y as abnormalities in these chromosomes can still lead to live births of babies, but with disorders such as Down Syndrome.
A more advanced and reliable alternative to FISH is Next Generation Sequencing (NGS) using the most advanced technologies testing all chromosomes. We use a technique of Next Generation Sequencing PGD (NGS PGD) to screen for abnormalities.
Who would benefit from PGS?
You will benefit from NGS PGD if you have experienced:
- Recurrent miscarriage
- Clinical aneuploidy (Down syndrome) risk
- Multiple pregnancy risk
- Sex-linked genetic illness risk
- Advanced maternal age (Above 35 years old)
- Family history with chromosome problems
- Multiple failure in IVF treatments
- Avoid deliver baby with chromosome problem
After screening for chromosomal abnormalities, healthy embryos can then be selected for implantation or cryopreservation via vitrification (“flash freezing”) or traditional slow-freeze method, depending on the circumstances, for future frozen embryo cycles.
Without genetic testing, there is a higher chance of implantation of a chromosomally abnormal embryo, which can result in a miscarriage or baby born with birth defects.
Using PGS, we can analyse and select embryos before they are implanted in order to reduce the risk of miscarriage, reduce the chances of having twins due to reduced need to transfer multiple embryos, and to achieve your family balancing preference.