Ethical aspects arising from non-invasive fetal diagnosis
Introduction
Testing or screening for fetal abnormality has fundamentally changed women's experiences of pregnancy. The advent of ultrasound, amniocentesis, chorionic villus sampling (CVS) and maternal serum screening (MSS) have enabled health professionals to offer women several sources of potentially significant information about the health of their fetus. Yet although these technologies do allow women to make informed choices in pregnancy, each is subject to limitations. Ultrasound can only detect physical abnormality, amniocentesis and CVS carry a small risk of pregnancy loss and MSS provides only a probability of harm, which can be difficult to interpret.
In the past decade, the isolation and analysis of free fetal DNA (ffDNA) or whole fetal cells in maternal blood has emerged as another method for testing during pregnancy. These technologies, explained in more detail elsewhere in this special issue, aim to offer non-invasive prenatal diagnosis (NIPD) to provide definitive molecular or chromosomal information about the health of a fetus without posing a risk to the pregnancy.1 NIPD is now beginning to change the landscape of prenatal testing: tests on ffDNA are already proven for fetal gender, rhesus D blood type and some Mendelian conditions such as achondroplasia. More tests are under development, including aneuploidy detection and Down syndrome.2 For the purposes of this chapter, NIPD is assumed to be clinically valid, with a predictive value commensurate to invasive methods.
The impact of NIPD on fetal medicine and pregnant women is predicted to be significant and ethical issues will arise.3 In contemplating the implementation of this technology, we can ask whether aspects of NIPD give rise to new ethical questions, or whether we are instead required to revisit existing dilemmas in prenatal diagnosis. NIPD is not the only non-invasive procedure available to women during pregnancy; ultrasound and MSS are also non-invasive. But unlike these existing methods, NIPD can offer definitive information about the health of a fetus at an early stage of pregnancy without putting the pregnancy at risk. Arguably, this gives rise to new nuances in ethical debates over prenatal diagnosis, perhaps most importantly the implications for informed consent. Yet existing issues in prenatal diagnosis will continue to be relevant, and for this reason these debates are briefly rehearsed in the following section.
Section snippets
Ethical issues in prenatal diagnosis
As a source of information about the health of a fetus during pregnancy, NIPD raises ethical issues familiar to anyone with experience of prenatal diagnosis (PND). Several existing issues in PND remain unresolved and, as the molecular bases of more and more conditions affecting health are identified, the dilemma of what constitutes a permissible test remains acute. The development and implementation of NIPD will raise new ethical concerns but these should also be assessed against existing
Advantages of NIPD
Despite the ethical issues arising in the provision of PND, NIPD might offer some practical (and therefore ethical) advantages. Primarily, NIPD could reduce the number of miscarriages caused by PND, as amniocentesis and CVS carry a small risk of pregnancy loss. A ‘normal’ result from NIPD—a test that poses no risk to the pregnancy—could mean that fewer women undergo further invasive testing. However, not all women might be reassured by a normal NIPD result. One North American study examining
Informed consent and informed choice to NIPD
A decision about testing or screening in pregnancy carries significant weight and can have far-reaching implications for women. To this end, any decision about NIPD should be made in accordance with a suitable model of informed choice or informed consent.
The operation of informed consent and informed choice are subtly different. Informed consent tends to be applied in situations where a woman is facing a designated diagnostic test. Three elements need to be satisfied: the provision of
NIPD and fetal sexing
The first application of NIPD was to determine fetal sex, as the detection of Y-chromosome DNA in a pregnant woman offers a robust prediction of a male fetus. This might be more predictive than ultrasound and easier to provide than other invasive molecular methods of determining sex that necessitate access to clinical services. Indeed, commercial providers of NIPD for fetal sex are already operating.29, 30, 31* The ethical implications of prenatal sex determination are well-addressed in the
Other non-medical uses of NIPD
Fetal sex might not be the only non-medical application for which NIPD is sought. Women or couples might also be interested in using the technology ‘for information only’, or to undertake a prenatal paternity test.
Regulatory issues in the provision of NIPD
The simplicity of obtaining samples for NIPD gives rise to the prospect that this technology will be made available on a commercial basis, perhaps circumventing clinical professionals altogether. This property of NIPD means that policy and regulatory issues regarding the availability of this testing need to be addressed soon. Annas recognised this potential problem over a decade ago.42 He proposed three alternative models for control of NIPD: the medical, market and regulatory models.
Under the
Conclusion
Non-invasive prenatal diagnosis is a promising technology. It will simplify many aspects of testing and screening in pregnancy, but will also introduce some new complexities. NIPD also forces us to revisit existing debates in prenatal diagnosis, to determine how they might change and what safeguards might be required.
At the very least, some of the questions that should be applied to NIPD are: Why is this test being considered at this stage in pregnancy? What benefits and concerns might it give
Acknowledgements
The author acknowledges Dr Lyn Chitty, Professor Angus Clarke, Dr Elizabeth Dormandy, Professor Theresa Marteau and Ms Ananda van den Heuvel for helpful and thought-provoking discussions. This chapter will inform a larger analysis to be undertaken by the author in 2008, funded by the SAFE Network (http://www.safenoe.org).
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