PGD and PGS procedures; Preimplantation Genetic Diagnosis & Screening

FlyToTreat/Articles/ PGD and PGS procedures; Preimplantation Genetic Diagnosis & Screening

 

Having a child suffering from a genetic disorder can be so painful and heartbreaking for both the parents and the child. Today with the advancement of medical technology, diagnosis of birth defects is possible through Preimplantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS).

Both PGD and PGS are laboratory procedures designed to test embryos before implantation to reduce the chance of having a child affected by genetic disorders. Genetic screening has saved many couples (especially those who are related) from having a child with birth defects.

 

What is Preimplantation Genetic Diagnosis (PGD)?

 

Preimplantation Genetic Diagnosis (PGD) is used for genetic testing of an embryo to look for a certain gene mutation(s) when the biological parents are already aware of the possibility of having a genetic abnormality in their embryos. PGD applies when one or both of the parents carry a genetic mutation. Therefore, PGD tries to detect specific disorder that has a high risk of being passed on from parents to their offspring.

PGD and PGS procedures

What is Preimplantation Genetic Screening (PGS)?

 

PGS is often an attempt to screen the embryo to prevent chromosomal abnormalities in the embryo even though there is no known reason for genetic abnormality in either one of the parents and they seem to be normal. PGS screens biopsied cells taken from the embryo for potential genetic disorders known as aneuploidy.

An important note: Both PGD and PGS expressions refer to the screening process applied on embryos to prevent implanting the embryo carrying genetic abnormalities. Therefore, they can often be used interchangeably.

 

How is PGD/PGS performed?

 

The process of PGD/PGS happens through a cycle of in vitro fertilization (IVF) so that the embryos are available in the laboratory for testing. Growing embryos have some cells named blastomeres that can be removed without any harm. By removing one or two blastomere cells out of the embryo, they will undergo genetic tests. The results are often ready in one or two days and then only normal embryos are transferred into the patient’s uterus to grow.  

Human cells have 23 pairs of chromosomes. Some chromosomes are more likely to be unpaired and lead to fetal death or birth defects such as Down syndrome (trisomy 21). Translocation condition happens when a chromosome breaks apart and attaches to other chromosomes. To check normal chromosome pairing, a technique called fluorescent in situ hybridization (FISH) is used.

How is PGD/PGS performed?

Who should consider PGD/PGS?

 

PGD/PGS is recommended for couples who have a history of inherited disease in their families. For these people, genetic testing may need to be performed to identify gene mutations before uterus implantation. In addition to the existence of known genetic abnormalities, PGS is recommended under the following conditions:

  • Couples interested in gender selection
  • Women age 38 and above
  • Couples who are interested in a single embryo transfer
  • History of recurrent miscarriages
  • History of multiple failed IVF cycles

Can PGD/PGS improve the chance of conceiving through IVF?

Can PGD/PGS improve the chance of conceiving through IVF?

 

Definitely yes. Even embryos that look normal may have aneuploidy. Transferring these embryos would result in miscarriage or giving birth to a child with a chromosomal disorder. PGD/PGS helps the embryologist to choose the healthiest embryo for implantation; therefore, the IVF success rate is improved. Furthermore, by having the ability to identify normal embryos, there is no need for transferring multiple embryos, so it prevents multiple pregnancies.

Is PGD safe?

The data that has been gathered from PGD live births in both humans and animals for many years shows that there is no more increase in birth defects compared to the general population. Based on the follow-up evaluations of children who were born after the PGD process, there are no noticeable effects on the growth or neurological development of the babies. Removal of a few cells from an early embryo does not stop the embryo from developing. By detecting the birth defects in the early stages, PGD can decrease the rate of miscarriage due to chromosomal disorders and have healthier pregnancies.

PGS for Sex Selection

PGS for Sex Selection

 

Through the IVF process, eggs and sperms are conceived in the laboratory and make a couple of embryos.  The embryos grow for 24 hours or longer before they are ready for testing. You can decide what kind of test should be done on the embryos. The embryologist carefully removes a few cells from the embryo (s) to be tested.

When they are looking for chromosomal abnormalities, they determine which embryos are male and which are female. Then you can decide about which gender you want to transfer. Your doctor transfers the embryo into the recipient’s uterus (you or a surrogate mother). After about two weeks if the result of the pregnancy test is positive, pregnancy successfully happened.

 

IVF and Sex selection in Iran

 

PGD is one of the advanced techniques, which is practiced in Iran’s infertility treatment centers.  By the use of PGD testing, genetic abnormalities in the embryos are identified before they are implanted into the mother’s uterus. PGD is also used for gender selection for couples who prefer certain gender. This procedure could be carried out due to the risk of inheriting a gender-related disease or for family balancing.

As it was mentioned before, the PGD technique is used through IVF technology. The cost of IVF+PGD in Iran is about $4300, which is an economical offer for couples from all over the world. While the quality of services is compatible with American and European countries, the cost of accommodation, meals, etc. is so affordable in Iran that made this country the number one destination for fertility treatment in the region.

 

 

IVF and Sex selection in Ukraine

 

There are different legal restrictions regarding gender selection in many countries, which is why many patients choose to follow sex selection abroad. However, sex selection is allowed in Ukraine according to its regulated laws. IVF and PGD treatment in Ukraine cost half as much as in Britain or the USA. The low cost of fertility treatment in Ukraine has made this country an attractive destination for international patients. The cost of IVF and PGD procedures in Ukraine is about $7000, which is a reasonable cost compared to other countries.

IVF and Sex selection in different country

PGD/PGS in India 

 

PGD test in India is performed only for detecting genetic disorders, and sex selection is outlawed by the rules of the country. India is one of the well-known countries in the field of infertility treatment that has attracted many medical tourists from around the world. The cost of IVF plus PGD treatment in India is around $6000, which is affordable for almost every class of people.

 

PGD/PGS in Turkey

 

Turkey is becoming one of the world’s preferred destinations for medical treatment offering healthcare services to couples who seek fertility treatment abroad. In Turkey, the cost of IVF+PGD for each embryo is about $5100. This service is practised in several clinics and hospitals. The treatment costs in Turkey are more affordable compared to many other countries. Patients who come to Turkey in the summer make an appointment with the health institutions located in the holiday resorts so that they can have a holiday and their treatments with specialist doctors at the same time.

MEDICALLY REVIEWED BY: Dr. Ali Bazazi

AUTHOR: Leila Nazari

27 June 2023 - Updated At: 13 May 2024

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