Is PGS / PGT-A really necessary for an egg donation cycle? Why not do Genetic Testing on the egg donor's blood sample?

A couple of months ago, before all the coronavirus lockdowns, me and my husband visited and inquired about egg donation at three Malaysian IVF clinics. All 3 clinics strongly advocated that we should use PGS / PGT-A with egg donation. They told us that because it is difficult to verify whether the anonymous egg donor has a family history of genetic diseases, we should play safe by using PGS / PGT-A. Apparently, the only information about the donor's family heath history comes from a Questionnaire form that is filled by the donor herself, and the reliability of such information cannot be guaranteed. Additionally, these IVF clinics also attempted to hard-sell PGS / PGT-A by touting the use of the procedure for sex selection, and trying to play on our biased preference for either a boy or girl.

However, I became skeptical when I came across a newspaper article in Today Online entitled: “Overseas egg donors — what Singaporean women should be wary of”. The article suggested that similar genetic tests on the egg donor's blood sample is a much cheaper alternative to PGS / PGT-A for screening the presence of defective genes carried by the prospective egg donor. What I understand is that there is much more DNA genetic material within a blood sample containing thousands of white blood cells, as compared to just a few cells from an embryo biopsy during the PGS/PGT-A procedure, which makes it easier and cheaper to do genetic testing. This made me wonder why none of the 3 clinics that I visited bothered to suggest genetic testing of blood samples. Could this because they wanted to earn extra money from the PGS / PGT-A procedure, rather than doing what is best for the patient? If that is the case, I am extremely angry that the clinics played on our fears of potential genetic defects carried by the anonymous egg donor.

Here is an excerpt from the article:
https://www.todayonline.com/commentary/overseas-egg-donors-what-singaporean-women-should-be-wary

Other claims may have less scientific basis. For example, many foreign fertility clinics strongly encourage their patients undergoing egg donation to utilise preimplantation genetic screening (PGS) to detect genetic defects in the conceived embryos, due to the unknown genetic heritage of the anonymous foreign egg donor. Yet they often neglect to tell patients that similar genetic screening of the donor’s blood sample is much cheaper than PGS.

Patients must also be aware that PGS is not a fool-proof method to detect genetic abnormalities in embryos, despite its high costs.There is a only a limited panel of common genetic diseases that PGS will detect, so it is impossible to screen and verify the entire genome of each individual embryo to be free of genetic defects. One notable example that cannot be detected by PGS is Autism Spectrum Disorders that are caused by multiple genes interacting with multiple factors within the birth environment. Additionally, if the egg donor is very young, it is unnecessary to utilise PGS to screen for Down syndrome that usually arises from genetic abnormalities in the eggs of older women.

Although many fertility clinics claim that PGS can improve the IVF success rates of older women, this only refers to older women using their own eggs, which have a high incidence of genetic abnormalities. PGS will not improve the success rates of older women using a young egg donor.

It must also be noted that PGS is not completely risk-free. There is a small chance of damaging the embryo as this delicate procedure involves drilling a hole through its protective shell (zona), to extract cells for genetic testing.


 

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Here are some interesting video podcasts that cast doubts on the necessity of utilizing PGS / PGT-A in egg donation cycles:


 
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In Malaysia, egg donors are required do blood tests for HIV, HepB and Syphylis at the IVF clinic itself. That is precisely why I am wondering why the IVF clinic cannot just collect extra blood samples for genetic testing at the same time. When I visited those IVF clinics, I was still ignorant so I did not ask about genetic tests on the egg donor's blood sample. It was only after reading the above article that I realized that IVF clinics may be deliberately trying to downplay this alternative option to PGS. It is no wonder that the MOH in Singapore is so strict in banning PGS / PGT-A in private IVF clinics, and allowing only a strictly-regulated clinical trial at government hospitals.
 
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False positives during PGS / PGT-A may arise because of mosaic embryos that contain a mixture of genetically abnormal and normal cells. There have been many reports that these mosaic embryos can give rise to normal healthy births. So the cumulative chance of success may not increase by PGS / PGT-A and may even decrease by excluding "mosaic" embryos, that could have developed into a healthy normal baby. As seen in the attached diagram of a blastocyst stage embryo, the ICM gives rise to the embryo, while the TE gives rise to the placenta and yolk sac. Testing a few cells from the TE only gives you a probability about what's going on in the ICM. An embryo with abnormal (aneuploid) TE but normal ICM most likely will still make a healthy baby.
 

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You can ask your egg donor agency to privately arrange genetic testing of the egg donor's blood sample, instead of doing much more expensive PGS / PGT-A (embryo genetic testing) at the IVF clinic.

Here are the contact information of various DNA-testing companies in the greater KL region:

Genomix Lab
Email:
[email protected]
Website address: www.genomixlab.com
Address: No. 47-3A, Level 3, Jalan PJU 5/12
Dataran Sunway, Kota Damansara
47810 Petaling Jaya, Selangor DE, Malaysia
Tel: +603 6157 2299

Map My Gene Sdn. Bhd.
Email:
[email protected]
Website address: https://mapmygene.com/contact-us/
Address: #05-16 Sunway Velocity,
Designer Office, Jalan Peel,
Kuala Lumpur 55100, Malaysia
Tel: +65-9028-9745 (Singapore telephone number)

Gribbles Pathology Malaysia
Email:
[email protected]
Website address: Address: 2nd Floor, Wisma Tecna
18A, Jalan 51A/223
46100 Petaling Jaya, Malaysia
Tel: +603 78417752

PrimaNora
Email:
[email protected]
Website address: Address: B1-13, TTDI Plaza,
Jalan Wan Kadir 3,
Taman Tun Dr Ismail,
60000, Kuala Lumpur,
Malaysia
Tel: +603 7728 2886

DNA Laboratories Sdn Bhd.
Email:
[email protected]
Website address: http://www.dna-laboratories.com
Address: B1-3 & B1-4, Block Plasma, UKM-MTDC Technology Centre, Universiti Kebangsaan Malaysia, 43650 Bangi, Selangor, Malaysia.
Tel: +603-8925 2700
 

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