Antenatal screening - what’s it all about?
This is a transcript of a talk given at the Royal Society of Medicine, Spring 1997
When I was first asked to speak tonight I was deeply flattered. I was also intrigued and challenged.
I went first to my own library of books and research papers. But couldn’t find what I was looking for. I pillaged the files of my colleagues at other journals, but could find no joy. I did a MEDLINE search - I did several MEDLINE searches - each of which turned up the occasional gem in the midst of all the usual rubbish. I turned to the MIDIRS database and the BMJ library with pages of enquiries which I thought would lead me to the answer. To my dismay, my first draft of this talk was over an hour long and still, to my mind, woefully incomplete!
Somewhere in the midst of all this obsessive activity it occurred to me that in searching for the answer to “What is ante-natal screening all about?” I was, in fact, acting out the problem.
Scientific research cannot provide the answer to our most difficult questions; questions which arise from the constant interplay between our hearts, minds, bodies and souls - it can only point us in useful directions. In the same way the continual poking and prodding, the searching and re-searching of ante-natal testing cannot provide the answers for us either. It may occasionally point us in useful directions, but only if we first have some understanding of what we’re looking for and why.
Discussions about ante-natal testing can be vast and complex. They can turn up more questions than answers. Often we try to simplify them by limiting our focus to medical parameters. But in reducing ante-natal testing to a medical issue, we also reduce our ability to explore and to understand.
What’s more, a reductionist approach can leads to defensiveness amongst those who practice it: “We’re only trying to help”, “What’s wrong with wanting every baby to be perfect and beautiful?” or “Why do you want to make women feel guilty about their choices?”
On first hearing these may seem like valid arguments. But on reflection several things fall into focus. Firstly, it is wrong to intimate that ante-natal testing makes perfect, beautiful babies. It is the parents who make the baby. How the mother takes care of herself and is taken care of by those around her, the kind of environment she lives in, and the kind of emotional support she has from her family, friends and her midwife are probably more influential in creating a perfect baby than a schedule of regular screening tests.
Secondly, women already feel guilty about their choices. Indeed, guilt is one of the primary weapons in the practitioner’s arsenal. So many women begin their pregnancies desiring as little medical interference as possible. Once in the system of maternity care, however, they are made to feel guilty about not wanting a scan or refusing a blood test, for putting on too much weight, or too little weight, for eating the wrong foods, having the occasional glass of wine, and later for expressing an interest in a home or water birth.
In spite of all this, I believe it’s fair to say that there is a general feeling amongst women that ante-natal screening is a good thing. They perceive it as an important part of their care and don’t always think of less invasive procedures such as serum screening or ultrasound as tests at all. Instead they see them as a way of addressing any fears they might have about their babies[i]. Today we take women’s fears, especially those of first time mothers, for granted. And yet, in a society where perinatal morbidity and mortality are so low, it is also fair to ask, what is it that makes women fear the worst?
Feelings of anxiety are natural to pregnancy - as natural as they are to any other major life transition. A woman might fear miscarriage, fear for the baby’s well-being, fear for her ability to cope with labour or parenthood, fear her partner’s reaction to her pregnancy. Anxiety may also be tied up with a shift in self perception. Woman today - as always - function in multiple social roles Taking on yet another role - that of mother - will involve a period of anxiety which may be reflected, in part, in her feelings about her baby.
On a cultural level, routine testing - whether it’s the seemingly trivial ritual of weighing a woman in or the more invasive amniocentesis - reinforces some powerful insecurities. Since women are rarely brought up to believe in the perfection of their bodies, pregnancy can be a time of great uncertainty. After all, how can the female body, so widely perceived as imperfect and dysfunctional, create a perfect baby?
From a clinical point of view, some of the “risk” factors as defined by doctors and midwives across the country appear mainly to increase women’s “risk” of anxiety. A woman will be told she is “at risk” if she is, among other things: under 18 or over 36; if she is having her first child or has had four or more children; if she is uncertain of the date of her last menstrual period; if she has had a previous small baby or a previous large baby; if she has had a previous caesarean; if she has had a previous long labour or a previous short labour; if she has had a previous forceps delivery; if she was over weight before conception or was underweight before conception; if she is too short (under 5 feet); and if she has put on too much weight during pregnancy or has put on too little weight during pregnancy. The results, as I ‘m sure you can see, are unbelievably narrow parameters for defining a woman as 'low risk'.
What this means is that many normal and healthy women end up being labelled 'high risk' even though only 10-30% of those allocated to high risk groups actually experience the adverse outcome for which the scoring system declares them to be at risk.[ii]
Also when ante-natal testing becomes an impersonal exercise, performed in an atmosphere of clinical efficiency by people with little or no communication skills, this can increase anxiety even more.[iii] It can also discourage women from asking necessary questions - questions which have relevance to them, the answers to which might provide genuine reassurance.
But today we address them not with simple, human reassurance but with technology. And because we find it so hard to accept that negative and positive feelings can co-exist in pregnancy, labour and beyond,[iv] - and that women do not need to be “saved” from this paradox - we use what we believe to be the certainty of screening tests to address women’s uncertainty. In the process we have somehow convinced women to take on board the medical model of ante-natal care; in other words to use screening not to confirm normality but to detect abnormality.
Given all this couldn’t then we speculate that women’s high uptake of screening tests is the result of irrational fear and compliance, rather than a proactive decision making process. We must also consider that if fear can motivate women to “choose” screening it could also motivate women to “choose” other inappropriate interventions in the name of safety, reassurance and protection. Can it be that ante-natal screening is what pushes women into hospital to have their babies, believing, in spite of the evidence, that this is the safest place, the place which will guarantee them a perfect child?
The Spectre of Down’s
From where I stand the guarantees we offer women are about as sound as those offered by used car salesmen and women should definitely be encouraged to read the fine print! Down’s syndrome - with its relatively high survival rate and obvious physical characteristics - is one abnormality which we can detect with relative ease. But our disproportionate focus on Down’s means that many women believe that, having been given the all clear, they can enjoy peace of mind for the rest of their pregnancies.
But there are over 5000 different chromosomal abnormalities. While ultrasound has a relatively high rate of detection for Down’s, it is rather less successful at detecting other kinds of abnormalities such as circulatory[v] and urological defects.[vi] It can also reveal “problems” which correct themselves during the course of the pregnancy and anomalies the significance of which we simply do not understand.[vii] Telling a mother about these can cause untold anxiety - even years after her baby is born perfect and healthy.[viii] Unfortunately we rarely reveal any of these possibilities to women.
Instead we focus on the sexy stuff, the exciting stuff. Today we can perform genetic modifications on unfertilised eggs. We can correct abnormalities the impact of which are unknown to us. Through this, and the more everyday act of ante-natal screening we are, in a very real sense, weeding out the bad eggs - all the time unaware, or unwilling to accept, that the bad eggs in our society are more likely to be the result of our own bad habits and not some obscure deficiency in women’s bodies.
It seems me, that nobody wants the blame for these bad eggs. So, I was interested in Theresa Marteau’s study on the attribution of “blame” for Downs syndrome children, and so grateful to see that she is speaking here tonight too. In it, several groups were asked to judge two vignettes: one, a Downs child born to a mother who refused screening; the other, a Downs child born to a mother who was not offered screening.[ix] The presence or absence of screening was the single most important factor influencing the attributions of blame and control following the birth of a Downs child. The outcome also suggested that all of us, lay people and health professionals, make judgements about women’s roles in the birth of children with disabilities. In another study from New Zealand women also expressed a fear of being blamed for producing an abnormal baby.[x]
The way we apportion blame is not just an emotional issue. It has implications for care and clinical practice. Those women who are perceived as having had control over whether or not they had an affected child, seem less likely to get sympathy and thus help and advice, in the substantial life adjustment needed to enter into the care of that child.
In addition, even as our focus on Down’s is being fine tuned, doctors in America appear to be having some success in reversing some of the worst aspects of Down’s through the early application of nutritional therapy[xii]. This work is in its infancy and is by no means totally convincing - but we have to ask ourselves, what if they’re right?
Finally, to the tests themselves. I believe it was Winston Churchill who once said that there was nothing so exhilarating as being shot at and missed. The macho/medical version of pregnancy perceives the abnormal baby as the proverbial bullet with your name on it, and screening tests as the camouflage which gives you the edge.
But how much of an edge do they really give us?
Because it is relatively non-invasive and there is no risk of miscarriage, many women will agree to an AFP, double or triple test in the hopes of finding reassurance and believing they have nothing to lose. In fact they have a great deal to lose because the tests' high false-positive rate means that large numbers of women spend a significant proportion of their pregnancies believing they are carrying “damaged goods”, only to find out after a battery of other tests that there was nothing to worry about after all.
Ultrasound can be just as hit and miss. It has already been established that routine scanning does not improve outcomes for babies.[xiv] Not long ago, at a hospital in Cardiff, several women were diagnosed as having dead babies and told they must have a termination, only to find out, just before the procedure, that actually their babies were alive and well.[xv]
A recent report on the findings of a large trial in West Yorkshire revealed that 1 in 200 babies terminated because of abnormalities detected by ultrasound was, in fact, perfectly normal. It also showed that, in 1 out of every 100 cases, ultrasound failed to detect significant handicaps for which mothers should be offered a termination.[xvi] Our colleagues at MIDIRS were responsible enough to put this statistic in their Informed Choice leaflets. However, this appears to have antagonised some doctors who refuse to distribute them - lest we make women feel anxious or guilty.
And so we come full circle. And perhaps it’s time to ask what’s so wrong with feeling anxious and guilty? Anxiety and guilt, when they are not being foisted upon us in some obscene power game, can be powerful catalysts for self-improvement. They can illuminate the places in our lives where things are not as they should be. This is as true in pregnancy as it is at any other time of life.
The vast majority of babies are already healthy. Screening has not changed this. But should a test reveal an abnormality often there is great pressure brought to bear on the woman to terminate her pregnancy.[xviii]
For some this is the best option. Others may be unaware that they have a choice.[xix] Still others believe that this is the best option only to find that they and their families experience emotional turmoil for years afterwards.[xx] But for others there may be more to gain from allowing the pregnancy to take its course and to see their child born, even if it only lives for a few hours or days.[xxi] We must also acknowledge that late terminations are, in all but name, labours. Some mothers may derive great comfort in having them treated as such by everyone around them. The offer to inject the baby with potassium in order to kill it before it is born may, in the end, be the cruellest, most insensitive thing a practitioner could do.
In truth, we have always found dealing with disabled children a problem. Certainly the solution of ending their lives is not new. The difference between “then” and “now” is that in the absence of ante-natal screening a mother would have taken the decision to end the life of her child after it was born. She was dealing in a real way with a real situation. Today we ask mothers to make life or death decisions on the basis of abstracts and guesswork. We prefer the “civilised” option of ending the child’s life before it is born. While this may help to put abnormality behind the screen, and help to protect us from our own, often conflicted feelings, about it, the result for the child is still the same.
When deciding about special tests, women don't just grapple with the endless sets of abstract percentages and risk scores. They grapple with the reality of their own lives, their values, emotions and perceptions of themselves.[xxii] They grapple with practical considerations - the money, time and energy it would take to raise a handicapped child and the effect it would have on their family and marital relationships. When deciding about termination they grieve - even as they are deciding - for their wanted child, for their hopes and for their dreams.[xxiii]
With an increased knowledge of these issues doctors, midwives and ante-natal teachers and lay volunteers, can advise and support women as they feel their way through this difficult process. Certainly a woman’s decision to choose or refuse a test, and everything which follows it, should be based on good information. Yet, most women’s knowledge about ante-natal screening is still very limited. [xxiv] Sometimes this is because practitioners convey little information or present it in a way which is misleading.[xxv] This can be because of their own ignorance[xxvi] or because they assume that too much information will worry or confuse mothers.
[i] Green et al, in Chard, T et al (eds), Obstetrics in the 1990s: current controversies, London: MacKeith Press, 1992, 65-89.
[xi] Brand, IR, et al,; Br J Ob Gyn, 1994; 101(5): 392-97.
[xv] Robinson, J, AIMS Journal, 1994; 6(4): 9-10.
[xvi] Brand, IR, et al, Br J Ob Gyn, 1994; 101(5): 392-97.
[xviii] Rothman BK, Birth, 1990; 17(2): 81.
[xix] Chitty, LS, BMJ, 1996; 313: 478-80.
[xx] White-van Mourik, MC et al, Prenat Diagn, 1992; 12(3): 189-204; Iles S, Baillieres Clin Obstet Gyn, 1989; 3(4); 769-90; Dallaire, L et al, Prenat Diagn, 1995; 15(3): 249-59.
[xxi] Watkins, D, The Practitioner, 1989; 233: 990-92.
[xxii] Kolker, A, Burke, BM, Women & Health, 1991; 20(4): 37-57.
[xxiii] Kolker, A, Burke, BM, Health Care Women Int, 1993; 14(6): 513-26.
[xxiv] Marteau, TM et al, J Psychosomatic Res, 1988; 32(4) 403-8.
[xxv] Marteau, TM et al, Pub Health, 1992; 106(2): 131-41.
[xxvi] Smith,Dk, et al, Quality in Health Care, 1994; 3: 75-8.
[xxvii] Thornton, JG et al, BMJ, 1995; 311(7013) 1127-30.