We are happy to announce the availability of the below-mentioned tests at Southend Fertility & IVF.
We discuss all considerations on an individual basis with the patient; giving utmost attention to all factors involved in any fertility issue.
Before making any decision about genetic testing, we review each couple's history and offer the most viable option to them.
Preimplantation genetic diagnosis (PGD) and Pre-Implantation genetic screening (PGS) are tests done on embryos for a particular genetic disease that it may be at risk of inheriting from the parents.
Embryo Biopsy
Preimplantation Genetic Diagnosis screens an embryo’s quality at the chromosomal and genetic level. It can be performed for a patient at high risk of carrying an inheritable genetic disease. Using this technique, embryos that do not carry the disease can be selected for transfer.
A single cell from an 8-cell stage embryo is removed and sent off for testing. DNA analysis identifies embryos that are free of the disease, making them good candidates for transfer.
Why is Embryonic selection beneficial?
For patients with genetic diseases, selection of embryos most likely to implant and develop into a healthy child becomes extremely important. Historically, the microscopic appearance of the embryo was the only criteria available to the physician and patient for the selection of “healthy” embryos for transfer. Unfortunately, there is no correlation between embryonic appearance and genetic health. Perfect-appearing embryos can carry chromosomal abnormalities and “unattractive” embryos can be genetically normal.
Clinical indications for which PGD can be used include, but are not limited to:
- Aneuploidy testing for advanced maternal age and recurrent pregnancy losses(duplicated or missing chromosomes)
Embryo Biopsy for PGD and PGS
The process of IVF PGD, as well as IVF PGS, can be performed on the embryos that are in different developmental stages, therefore the biopsy procedure varies accordingly. In clinical practice, only two types of biopsy are used:
- Blastomere biopsy – (on day three at cleavage stage embryos) – 1 or 2 cells are removed from 8-cell embryo for genetic analysis
- Trophectoderm biopsy – (on day five at blastocyst stage embryos) – 4 or 5 cells are taken from the outer trophectoderm layer without affecting the inner cell mass from which the fetus later develops.
The Biopsy procedure always involves two steps. The first is the opening of the zona pellucida and the second being removal of the cell(s). Both the steps have different approaches, including mechanical as well as chemical procedures, but most advanced laser technology is used for breaching the zona pellucida
Using the advanced technology, the zona thinning is possible to create a point of herniation already at the time of ICSI procedure, that is less disturbing for embryo than traditional zona-opening. During trophectoderm (TE) biopsy we operate with accurately controlled laser beam to release the outer cells of the blastocyst.
The retrieved embryonic cells are then sent for genetic analysis by the use of microchip method. In this, a larger number of cells allows a more accurate genetic assessment of the embryo without affecting its further development. Once the cells have been extracted from a blastocyst, the embryos are then frozen and stored for a few days until the genetic results are available. The main limitation of the process of blastocyst biopsy is that usually, only a limited number of embryos will reach the blastocyst stage. Therefore, the final decision on biopsy approach should be left to our experienced specialists.
The benefits of PGD are as follows:
- PGD is an effective tool for more than 100 different genetic conditions
- PGD is performed before implantation thereby offering the couple the option to decide whether or not they choose to go ahead with the pregnancy
- PGD greatly reduces the risk of passing on specific genetic diseases to their biological offspring
Some single gene disorders identified using PGD technique are:
- Cystic Fibrosis
- Haemophilia
- Sickle Cell Disease
- Spinal Muscular Atrophy
- Thalassemia
- Huntington’s Disease
On the other hand, Pre-Implantation Genetic Screening (PGS) is used to denote procedures that do not look for a specific disease but use PGD techniques to identify embryos at risk. PGS identifies embryos that display chromosomal abnormalities that may result in IVF failure, miscarriage or babies born with Down’s Syndrome or Edward’s Syndrome.
Both PGS and PGD involve testing embryo cells. They both detect genetic irregularities in embryos prior to embryo transfer and thereby offer:
- Increased chances of pregnancy
- Decreased chances of multiple pregnancies
- Reduce chances of pregnancy loss
- Ability to avoid undesired genetic traits
IVF Success Rates with PGS and PGD
PGD IVF or Preimplantation Genetic Diagnosis is basically a reproductive technology used with an IVF cycle. It can be used for diagnosis of a genetic disease in early embryos prior to the stage of the implantation and pregnancy. Whereas Preimplantation Genetic Screening is the proper term for testing for overall chromosomal normalcy in embryos.
The best IVF PGD clinic in India then it can be judged on the number of best IVF success rates. It is critical to have an excellent culture system in order to get a maximal number of quality blastocysts for biopsy.
Both PGD and PGS have different purposes and screen for different genetic problems, that is why IVF Success Rates with PGS and PGD will vary. Many people having fertility treatment will not need to have either of these types of testing done, but in some cases, PGS or PGD may help your reproductive endocrinologist find healthy embryos to implant in your uterus during IVF treatment.