By John Kerr 11/09/2017


A new report from New Zealand bioethicists warns that prenatal screening technology is developing exponentially – and we need to think hard about how we use it.

The Judging Genes & Choosing Children report, funded by the New Zealand Law Foundation, digs into the ethical, legal and social issues posed by a new era of genomic testing for embryos and foetuses.

The hefty 342-page report considers a number of rapidly evolving genetic technologies that a woman may be offered, either during pregnancy or regarding embryos created by IVF (in-vitro fertilisation), including:

  • Non-invasive prenatal testing (NIPT), which enables foetal information to be gleaned from a maternal blood test as early as 10 weeks into pregnancy
  • Chromosomal microarray testing that may be performed at about 18 weeks following invasive amniocentesis
  • Preimplantation genetic testing of IVF embryos involving the latest high-resolution, next generation sequencing.

Lead author of a the report, Dr Jeanne Snelling of the University of Otago’s Bioethics Centre and Faculty of Law says a common feature of all of these tests is that they enable an increasing and significant amount of health-related information to be derived, compared with traditional prenatal tests, and all are associated with particular technical, ethical and legal challenges.

“The report considers how this new landscape reignites debates about the implications of new technology for women and how it affects the experience of pregnancy.”

Read more about the report on Scimex.org

For parents-to-be, these genetic tests can present a bewildering array of complex information and difficult decisions. Commercial companies are already “aggressively marketing” genetic tests to pregnant women, says the report. Currently such tests only screen for a handful of genetic conditions, most commonly trisomies (three copies of a chromosome instead of two) such as Down ’s syndrome. But more specific tests are already on the horizon, with research suggesting that the range of conditions that can be tested for will continue to expand.

Auckland-based company EasyDNA offers non-invasive prenatal testing (NIPT)

 

Complex decisions ahead

Existing testing already means parent face weighty choices, says the report.

“Parents may face decisional conflict, between continuing a wanted pregnancy and concerns regarding the potential quality of life of a child with additional and potentially complex needs.”

 

Many factors influence parents choices. Figure from Judging Genes & Choosing Children, Snelling, Kerruish & Lenagh-Glue (2017).

 

A key issue with NIPT is the accuracy and sensitivity of tests as they are further developed, says the report, cowboy operators may get ahead of the science and promise testing capabilities beyond the limits of the technology:

One of the controversial aspects of NIPT is the way in which commercial companies have aggressively marketed tests and extended NIPT screening panels to include additional trisomies, sex chromosome anomalies as well as microdeletion syndromes before having clear evidence regarding the positive predictive values of these less common anomalies.

The report strongly recommends that all NIPT procedures follow strict guidelines that include operators giving a full explanation of the tests current capabilities and caveats as well as proper follow-up on positive results.

IVF and preimplantation selection

It is a different story for prospective parents using In Vitro Fertilisation (IVF). Here, genetic testing of fertilised eggs gives clinicians (and potentially parents) the opportunity to choose which are selected for implantation. Clinicians already use such technology to identify embryos most likely to result in full term pregnancy. But the ability to select for non-medically relevant traits, like hair or eye colour is a real possibility for the future.

There is a massive conceptual change that comes with this kind of testing, warns Dr Snelling.

“There’s been a significant leap in the science – it’s a leap that few people anticipated 25 years ago, when the technology began,” she said when the funding for the report was first announced.

“It is by no means an over-statement to say that this type of testing, if incorporated into reproductive genetic medicine, promises to change the nature of conception. It would involve a conceptual shift from the current approach of choosing an embryo most likely to result in a successful pregnancy, to choosing the ‘best’ embryo based on a much wider set of criteria.”

Information overload

Dr Snelling says there is a “common assumption” that more information is always better.

“That is not always borne out in the empirical studies of women’s experiences.

“One recurring theme is the pressing need to ensure women and their partners have a genuine choice to accept or decline expanded screening or testing, and that those who do undertake it are provided with the necessary professional advice to ensure they are sufficiently informed, prepared and supported throughout.

“Expanded screening and testing is likely to not only affect reproductive outcomes, but also women’s experiences of conception and pregnancy in the future. The major issue is how all these technologies should be integrated into clinical practice here.”

So what do we do?

Ultimately the report finds that it is likely that more and more New Zealand fertility providers will take up prenatal genomic screening if the research shows it can reduce the time it takes for a woman to conceive, and increases the ‘take-home baby rate.’ The challenge lies in how the testing is used in the clinic.

The report offers some clear recommendations for implementing current genetic screening technologies but also offers some final broad questions to contemplate:

  • Are the risks of proportionate/disproportionate to the benefts?
  • What information do prospective parents want to know, and is it the same for all parents?
  • Do prospective parents have a duty to know certain information – should parents be able to “opt out” of receiving certain results?
  • Who decides what information is to be disclosed following testing – should this be professionally predetermined, based on a shared/negotiated agreement with clinicians or, alternatively, should the scope of genomic screening be predetermined by regulators or policy-makers?
  • Can the risk of psychosocial harm from preimplantation testing, such as increased anxiety, be mitigated?
  • What effect will extended testing have on the subsequent parent-child relationship?

These are tough questions, but ones we will have to answer in the coming era of prenatal genetic testing.