Free fetal DNA testing: Implications for the abortion debate

Jennie Bristow, editor of Abortion Review, examines the collision of scientific advances in prenatal testing with prejudices about abortion for fetal abnormality.

Of the approximately 200,000 women who have abortions in England and Wales each year, a very small proportion will terminate a wanted pregnancy following a diagnosis of fetal abnormality. Screening and testing for genetic or other abnormalities often occurs in the second trimester of pregnancy: therefore abortions for these indications often take place later in pregnancy, making them clinically and emotionally more demanding than first trimester abortions. Abortion for fetal abnormality has become a point of controversy, with Parliamentary and media attention tending to focus on abortion for disabilities such as Down’s Syndrome or cleft palate, conditions that vary in severity and may not be incompatible with life.

Women seeking abortion following a diagnosis of fetal abnormality have to contend with a number of pressures: their own emotions and resources for coping with a new baby with special needs, or a baby that cannot survive; service constraints; and a backdrop of media controversy and public misinformation, in some cases encouraged by groups as part of anti-choice campaigns. Advances in prenatal testing seem set to make the process of diagnosing certain fetal anomalies technically easier and available earlier in pregnancy, although these techniques may be some years away from the clinic.

One would hope that society would focus its resources on helping the minority of women who find themselves in such a situation. Unfortunately, while scientific developments are yielding some exciting possibilities for prenatal testing, the political context in which these developments are discussed risks trivialising and restricting women’s decision-making.

What the numbers tell us

Abortions for fetal abnormality constitute a tiny proportion of the total. In 2007, 1,900 abortions (one percent) were performed under ground E: ‘there is a substantial risk that if the child were born it would suffer from such physical or mental abnormalities as to be seriously handicapped’ (1). Abortions under ground E are legal beyond 24 weeks, but these are rarer still. In 2007, there were a total of 135 terminations for fetal abnormality after 24 weeks in England and Wales: 0.07% of the total abortion figure for that year.

Those abnormalities which prompt women to opt for abortion are typically chromosomal abnormalities or congenital malformations. In 2007, chromosomal abnormalities were reported for 39% of cases under ground E, and congenital malformations in about 46%. The most commonly reported malformations were of the nervous system (24% of all ground E cases) and the musculoskeletal system (6%). Down’s Syndrome (23% of all ground E cases) was the most commonly reported chromosomal abnormality.

It should be noted that not all abortions for fetal abnormality are recorded as such. Some prenatal testing, particularly for Down’s Syndrome, takes place earlier in the pregnancy than in the past, with screening now available at 11-13 weeks. This enables a diagnosis to take place before 24 weeks, and thus an abortion is legal under the more common ground C: ‘the pregnancy has not exceeded its twenty-fourth week and that the continuance of the pregnancy would involve risk, greater than if the pregnancy were terminated, of injury to the physical or mental health of the pregnant woman’. For women or clinicians who feel uncomfortable with specifying their reason to have
an abortion in terms of fetal abnormality, the ability to record the abortion in more general terms is important.

Developments in prenatal testing

For a woman carrying a wanted pregnancy and attending antenatal care, the first sign that there may be a problem with the fetus is through screening. With their consent, pregnant women are routinely screened according to National Screening Committee guidance, to assess their risk of carrying a fetus with a number of conditions, including spina bifida and Down’s Syndrome. If the screening flags up a potential problem, the woman will then be invited to undergo a diagnostic test. This is likely to involve an invasive procedure, such as amniocentesis or chorionic villus sampling (CVS), both of which carry a small risk of miscarriage and of which need to be carried out after 11 weeks of pregnancy.

For several years, the search has been on for an accurate form of non-invasive diagnostic testing that can be carried out earlier in pregnancy. Prenatal tests based on free fetal DNA (ffDNA) circulating in the woman’s bloodstream are now being developed. A useful explanation of ffDNA is provided by Tessa Homfray, Consultant in Medical Genetics at St George’s University Hospital, London:

‘For decades, attempts to identify intact fetal cells in the maternal circulation have been unsuccessful - too few cells were present, and the few that were identified could remain in the circulation for years. Cell-free DNA is also present in the circulation and probably arises from apoptosis (controlled cell death) of cells. Fetal DNA arises from dying trophoblast cells and comprises 3-6 per cent of the total cell-free DNA in the maternal circulation. FfDNA was first demonstrated in the maternal circulation in 1997, it consists of short fragments of DNA, not whole chromosomes. It can be first identified from the fourth week of gestation and increases throughout pregnancy. It is rapidly cleared from the maternal circulation after delivery and is undetectable by two hours [after the birth].’ (2)

The identification of ffDNA is a major breakthrough, allowing for diagnostic testing using a maternal blood sample well within the first trimester of pregnancy. The technique is easy to carry out, through a simple blood test, but challenging in terms of analysis. Scientists are still at the early stages in being able to use it accurately to diagnose a variety of fetal abnormalities. However, already two clinical uses of ffDNA are currently in frequent use in the UK. Rhesus typing enables clinicians to identify Rhesus positive babies carried by Rhesus negative women, and to try and prevent isoimmunisation of the fetus by using anti-D immunoglobulin. Fetal sex determination is another use, which is offered to women who are either carriers of a X-linked disorders and who only need to have a CVS if they are carrying a male, or women at a one in four risk of having an affected baby with congenital adrenal hyperplasia, who can be treated early on with dexamethasone. (3)

As Tessa Homfray notes, these two uses for ffDNA ‘are only the very beginning for what is potentially possible with this technology.’ Screening for Down’s Syndrome and other major trisomies (conditions caused by having three, rather than two copies of a particular chromosome) is one future possibility, as is identifying single gene disorders. Such developments would, as Homfray says, ‘transform prenatal diagnosis and screening’, making the diagnostic process earlier in pregnancy and without the risks associated with invasive tests.

Implications for abortion

The use of accurate diagnostic testing earlier in pregnancy has some clear implications for abortion. Women who opt for abortion following a diagnosis of fetal abnormality will be able to have the procedure earlier in gestation, giving them easier access to treatment and a wider choice of methods. Abortions in the second trimester of pregnancy constitute a minority – approximately 10% – of all procedures, and involve lengthier and more complex
interventions. Among women seeking surgical abortion for fetal abnormality, there has already been a small shift to using independent providers, because some NHS units will not provide surgical abortions after about 13 weeks, and many women are reluctant to undergo medical induction. (4)

Access to less risky and more widely available diagnostic methods would be a positive development for women who find themselves having to terminate a previously wanted pregnancy. That does not mean, however, that women will be more likely to opt for abortion, or that they will undertake it any more lightly. As Jane Fisher, Director of the charity Antenatal Results and Choices (ARC), explains, we should not assume ‘that an earlier diagnosis will necessarily be easier for parents to cope with. Making painful decisions about the future of what is most often a wanted pregnancy is difficult at any gestation. There is no evidence that earlier terminations for fetal abnormality have substantially less emotional impact on women and couples than those carried out later in the pregnancy.’ (5) Fears that earlier prenatal diagnosis will encourage women to abort fetuses that they would otherwise have carried to term trivialise women’s strong emotional investment in wanted pregnancies, and the seriousness with which they consider the decision to terminate following a diagnosis of fetal abnormality.

At a public discussion of ffDNA-based prenatal tests organised by Progress Educational Trust in September (6), members of the audience also raised concerns that early knowledge of fetal sex would encourage women to practice sex selection. This fear, often articulated by anti-abortion organisations, also indicates the degree to which women’s abortion decisions are over-simplified. Women in the UK are not known to demand abortions following their mid-pregnancy scan because the fetus is the ‘wrong’ sex, and there is no reason to assume that they would do so earlier on in pregnancy. As we have seen with the introduction of other important and exciting medical technologies, developments such as this one have tended quickly to lead to unfounded concerns about a ‘slippery slope’. The reductive argument posits that women given the opportunity to make decisions about their severely disabled fetuses will begin to request abortions for trivial and cosmetic reasons and is a discomfiting reminder of the skewed political and media environment in which abortion for fetal abnormality is often discussed.

Fetal abnormality and abortion law

During the Parliamentary debate on the Human Fertilisation and Embryology (HFE) Bill, at least two amendments were been tabled that proposed changes to the UK abortion law as it deals with fetal abnormality. Nadine Dorries, Conservative MP for Mid-Bedfordshire, sought to have written into legislation that the ground of abortion where there is risk that the fetus is ‘seriously handicapped’ should not include club foot, cleft lip, cleft palate and cleft lip and palate. An amendment tabled by Charles Walker MP, Conservative MP for Broxbourne, attempted to rewrite ground E, substituting ‘seriously handicapped’ with the phrase ‘so seriously handicapped that the child would be incapable of having or achieving a recognisable quality of life.’ Both these amendments trivialise the decision-making made by women and their doctors, who grapple with their decision in the context of clinical judgement and the unique pressures of their lives.

The amendment tabled by Nadine Dorries is a clear example of gesture politics, picking up on an emotive issue given prominence by a long-running anti-choice campaign and attendant media coverage. The issue of ‘abortion for cleft palate’ burst into the public arena in 2002-3, when Joanna Jepson, a photogenic curate who had had a congenital malformation of the jaw corrected, succeeded in bringing a judicial review of a case in which a woman had aborted a fetus after 24 weeks because of a similar anomaly that was likely to have been a marker for other much more serious conditions. The case, and the coverage of it, ran for several years, and involved the identification in the press of the doctors involved and a police investigation. The Crown Prosecution Service eventually decided that there was no evidence on which to base a prosecution, but the chilling impact of the case upon medical confidence was significant. For example, some health authorities now have an ethics panel to deal with each case of a post-24-week abortion: leading to further uncertainty and delay for the woman in that position, and raising ethical concerns about the duty of doctors signing for abortion delegating their responsibilities.

With the attempts to place further legal restrictions on women having abortions for fetal abnormality, anti-abortion campaigners are, says Jane Fisher, ‘trying to suggest that the law is too open, and that women are making all these outrageous decisions: and we know that’s not true. Women are not having terminations for minor clefts at 24-plus weeks, and it’s an insult to suggest they are.’ For example, cleft palate can sometimes indicate a more serious underlying genetic or chromosomal syndrome, which cannot be diagnosed with certainty. (7) By the same token, the assumption that giving a minority of unfortunate women bad news about their pregnancies earlier in gestation could lead to a wave of frivolous terminations is an insult to all women, implying that they cannot be trusted with information about their pregnancies.

There are some genuine ethical considerations surrounding ffDNAbased prenatal testing. For example, some women will not always want diagnostic tests, and it is important that women are properly informed of the distinction between the standard blood test for screening, and a blood test that might give a diagnostic result. There are also genuine ethical considerations surrounding abortion for fetal abnormality. The greatest of these is surely that women seeking abortion of a previously wanted pregnancy because of the discovery of fetal anomalies should not have to endure even more pressure and difficulty because of legal and service provision issues, and that screening and diagnostic tests should be the best available to prevent the possible loss of wanted pregnancies due to the testing procedures.

This is why advances in testing, which will allow those abortions to take place earlier, are to be welcomed. It is also one reason why retaining the 24-week ‘time limit’ for abortion is so important. Currently, women who have a diagnosis of abnormality at their mid-pregnancy (18-20 week) scan will find themselves having an abortion at a later gestation, as a result of waiting for further tests and needing the time to make their decision. While extremely few abortions happen after 20 weeks – about 1.5% - it is crucial to give women struggling with these difficult decisions the time and space to decide what to do.

Jennie Bristow’s article is the lead piece in the Autumn 2008 print edition of Abortion Review. Download this edition as a .pdf here.

References

(1) Abortion Statistics, England and Wales: 2007. Department of Health, June 2008
(2) ‘Progress in free fetal DNA (ffDNA)-based prenatal tests.’ By Tessa Homfray. Bionews, 15 September 2008
(3) ‘Progress in free fetal DNA (ffDNA)-based prenatal tests.’ By Tessa Homfray. Bionews, 15 September 2008
(4) Interview with Jane Fisher, 10 July 2008
(5) ‘Non-invasive prenatal diagnosis using cell-free fetal DNA: implications for parents.’ By Jane Fisher. Bionews, 15 September 2008
(6) Free fetal DNA: Testing the waters. A debate organised by the Progress Educational Trust in partnership with the Royal Society of Medicine, 23 September 2008, London
(7) ARC briefing, July 2008

Additional resources

Antenatal Results and Choices

BioNews: news, information and comment in assisted reproduction and genetics

Progress Educational Trust

Safe Network (The Special Non-Invasive Advances in Fetal and Neonatal Evaluation Network)