Recently, the Singaporean Ministry of Health (MOH) has implemented a new Co-funding and Medisave scheme for patients to undertake pre-implantation genetic testing (PGT) of embryos in IVF (in vitro fertilisation) treatment.
Nevertheless, this scheme covers only PGT-M (monogenic disorders) and PGT-SR (chromosomal structural rearrangements) for a very small number of IVF patient who are confirmed carriers of known genetic defects (40-50 couples a year). It does not cover the much larger number of older female IVF patients without any known genetic defects, but nevertheless are at substantial risks of spontaneous birth defects, most commonly Down syndrome.
As a woman gets older, there are increased risks of her eggs having an extra chromosome copy, which in turn results in spontaneous genetic defects. Besides Down syndrome caused by an extra copy of chromosome 21, older women also have increased risks of Edwards syndrome (extra copy of chromosome 18), Patau syndrome (extra copy of chromosome 13) and Klinefelter syndrome (extra X chromosome).
Although, such genetic defects in fetuses can be accurately diagnosed in pregnant women by non-invasive prenatal testing (NIPT), they have to face the agonizing dilemma of whether or not to abort their unborn child, upon getting a positive diagnosis. To avoid the moral dilemma and emotional trauma of abortion, it is therefore preferable for older women undergoing IVF to screen their embryos for genetic abnormalities, before transferring into their womb.
This may be achieved by a different type of PGT, known as PGT-A (pre-implantation genetic testing – aneuploidy), also commonly referred to as PGS (pre-implantation genetic screening). Currently, PGT-A (PGS) is still not approved as mainstream clinical treatment in Singapore, due to unclear results and a high attrition rate of 72% in local clinical trials, as reported by the Ministry of Health (MOH) in 2021 (MP Rahayu Mahzam on pre-implantation genetic screening, Channel News Asia, 2nd March 2021). Not only is PGT-A (PGS) highly-expensive, but it is also highly-invasive, as it involves drilling a hole through the embryo shell (Zona Pellucida) to extract cells from the embryo for genetic testing. This can potentially cause harm to the embryo and impair it’s development.
Recently, a much cheaper and less invasive alternative to PGT-A (PGS) was announced, with ground-breaking results of an international study being published in the reputable “Human Reproduction” journal. A novel artificial intelligence (AI) algorithm called “Life Whisperer Genetics” was successfully developed by healthcare company Presegen to accurately assess the genetic normality of embryos, based only on microscopy images. This is non-invasive, low-cost, and provides results instantly, which is very much preferable to the expensive, time-consuming and invasive PGT-A (PGS) technique.
Hence, the Singaporean Ministry of Health should consider obtaining licensing rights, implementing and subsidizing such new IVF embryo screening technologies to prevent Down syndrome and other spontaneous birth defects in older women undergoing IVF. This would thus save on the unnecessary expenditure of the many Singaporean patients who travel abroad to access PGT-A (PGS) with IVF treatment, as this controversial technique is still not yet approved as mainstream clinical treatment in Singapore.
Dr. Alexis Heng Boon Chin
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