Reproductive genetics: the accuracy of non-invasive preimplantation testing, to be debated

Reproductive genetics is one of the essential topics in ART today. Non-invasive pre-implantation genetic testing – are we ready? This is the interesting question posed at the round table discussion moderated by Dr. Nicolás Prados, Director of IVI’s IVF laboratory, on the last day of the 9th edition of the IVIRMA Congress. The use of traditional pre-implantation genetic testing is compared with the more recent, non-invasive methods. To analyse the advantages, disadvantages and characteristics of both, doctors Dagan Wells and Carmen Rubio participate in this round table.

Dagan Wells, who has devoted almost three decades to the study of embryonic genetic anomalies and their early detection, is a professor at the University of Oxford. In addition, he runs Juno Genetics, a state-of-the-art clinical diagnostic laboratory providing a wide variety of genetic tests related to reproductive medicine. For her part, Dr. Rubio is the Director of Embryo Genetics Research at Igenomix Laboratories.

A revolutionary approach

Prof. Dagan Wells agrees that, non-invasive testing of IVF embryos is “a revolutionary approach which offers a great deal of promise”. However, he cautions that such methods are not yet ready for use in clinics because the results they provide are not as accurate as more invasive methods. “We should be providing the best possible care for our patients and, at this time, I don’t believe that non-invasive tests are sufficiently reliable. There are too many false positives – embryos that are labelled abnormal when in fact they are unaffected by the genetic abnormality being tested. There are also too many false negatives – cases in which the embryo has an abnormality but is wrongly classified unaffected”.

Prof. Wells argues that errors in the results of non-invasive tests are sometimes so frequent that it is considered necessary to supplement the test with a follow-up performed using traditional invasive techniques, which “defeats the whole purpose of having done the non-invasive test in the first place” said Prof.  Wells. 

Detection of chromosomal abnormalities

The use of pre-implantation genetic testing is common in assisted reproduction treatments, helping to ensure that the embryos chosen for transfer to the uterus do not have any chromosomal abnormalities. “Embryos generated during an IVF cycle quite often have a chromosome missing or a duplicated one. This is a situation known as ‘aneuploidy’. If a chromosomally abnormal embryo – an aneuploid embryo – is transferred during an IVF cycle, in most cases it will not implant or will miscarry. Therefore, it is advisable not to transfer chromosomally abnormal embryos if they can be accurately detected”, explained Wells.

These tests are traditionally performed using a technique that is considered invasive and requires skilled professionals, as Prof. Wells describes: “A small number of cells are removed from the embryo, usually when the embryo is about five days old. The cells are then analysed using advanced molecular methods. The only problem is that the removal of these cells is a highly skilled procedure. It requires an embryologist who has done a lot of training and it also requires some expensive equipment.”

Reproductive genetics: non-invasive tests

Not all laboratories have the required skills, technology or equipment, which, according to Prof. Wells, causes “bottlenecks” that reduce patients’ access testing and increase costs. In contrast, non-invasive tests are carried out without the need to extract cells from the embryo, focusing their analyses on a tiny amount of genetic material that leaves the cells and passes into the environment in which the embryo is developing.

This has significant advantages, which Professor Wells summarizes as follows: “Any risk to the embryo associated with the removal of cells would be eliminated and the costs of the procedure could be reduced because clinics would not have to pay a very experienced embryologist nor have the expensive equipment required”. That is why Wells himself speaks of an “extremely exciting possibility” but insists that for the time being, more precision is needed in the results obtained, which invasive tests do offer. “I’m still convinced that non-invasive PGT-A has great promise for the future but I don’t believe it’s ready at this time”, he concluded.

Closure of the 9th International IVIRMA Congress

Today marks the end of the ninth edition of the Congress organised by IVIRMA Global, held for the first time in an online format, due to the global situation caused by the COVID-19 pandemic. Five days in which, in addition to the traditional lectures, through which the best researchers in Assisted Reproduction have presented the latest findings in the field, more interactive and dynamic formats have been sought.

Thus, it included different debates, conducted by experts, on the most relevant topics for the future of reproductive medicine and also Workshops run by leading figures in Reproductive Medicine. On this occasion, the audience was broadened to include not only medical and research staff but also other professionals linked to infertility and assisted reproduction, such as psychologists, family doctors and geneticists.

About the 9th International IVIRMA Congress

From 15 to 19 November, the 9th International IVIRMA Congress on Assisted Reproduction will be held, which attracts the main researchers worldwide in the sector. At this event we present the advances achieved in the field of Reproductive Medicine, the most innovative techniques and the results of the latest research. In addition, it is a meeting point for sharing best practices to improve the daily results in this activity. The Congress, the ninth edition of which is held online, brings together more than 1,000 specialists from 65 countries, and is held every two years.

About IVIRMA Global

IVI was founded in 1990, as the first medical institution in Spain fully dedicated to assisted reproduction. Since then, it has helped with the birth of more than 250,000 babies thanks to the application of the latest technologies. In early 2017, IVI merged with RMANJ, becoming the largest assisted reproduction group in the world. To date it has around 80 clinics and 7 research centres in 9 countries and is the leading centre for reproductive medicine. www.ivi.es – www.rmanetwork.com.