[The first part of this report of the Institute's 1992 symposium appeared in the last issue of the Newsletter.]
Fetal screening is presumed to be for the purpose of informing decisions to be made by parents about the treatment of the fetus, including termination of pregnancy. Among the ethical issues to be considered are:
The mother’s choice is not absolute - the doctor may decline to terminate a pregnancy merely to relieve disappointment over some normal characteristic, for example a child of unwanted sex where there is no sex-linked disorder. But, given an adverse prognosis, the presumption is in favour of her being free to choose.
The concept of autonomy - the right to make one’s own decisions - is much in vogue in medical ethics. But it can have no relevance to the position of a fetus.
Duty is fundamental to the traditions of our civilisation. We have a duty to protect the unborn child, even though it has no rights. The problem is to identify its interests and how they may best be served.
As it is an established parental duty to protect the interests of the fetus, the parent may give consent by proxy to what is responsibly held to be for its good and refuse consent to what is not.
There are inevitably difficulties in applying these principles. In particular, it is impossible to objectively measure abnormality and so establish when it is appropriate to overturn the presumption of right to life. Ultimately this is a moral decision.
The Warnock report concluded that the embryo of the human species is entitled to special status, yet can be owned, bought, sold and experimented upon. But in law an embryo, even less a fetus, is not a person. This does not mean that it enjoys no protection of its interests (eg to inherit) but the interests are contingent and vest only upon birth. Thus a child can sue for injuries sustained prior to birth; but no action is possible on its behalf for injuries which led to death before birth. The Human Fertilisation & Embryology Act 1990, without recognising the status of the fetus as either a chattel or a person, introduces a comprehensive regulatory regime for the treatment of embryos. The Act deals with both the protection of embryos from the consequences of manipulation and the legal rights over stored embryos where, for example, one or both parents have died. The subject is one where the law has struggled to keep pace with scientific advance; the courts are certain to be faced with difficult decisions in the coming years.
The emerging possibilities of fetal surgery must be evaluated in the context of other medical advances such as the ability to diagnose conditions much earlier in development and the major improvements in postnatal care of afflicted babies.
Once a malformation is detected in utero, the possible courses of action are as follows:
Fetal surgery may be justified if the following apply:
The two conditions which have been mainly susceptible to treatment so far are:
Hydronephrosis - obstruction of the urinary tract. One treatment is the installation of a vesoamniotic shunt but the complication rate is high at around 40% from the following:
It is too soon to draw firm conclusions on the value of the procedure.
Diaphragmatic Hernia - a hole in the diaphragm through which the viscera pass, inhibiting pulmonary development. Mortality from the condition is high and associated anomalies are common so that cases suitable for surgical intervention are few.
The concept of the fetus as patient has only developed as the risks of childbearing and pregnancy have lessened. The concept demands that the same precision in diagnosis is available as for the adult. Indeed, a very similar approach is appropriate - particularly the need for a good history and careful examination.
Developments in ultrasound technology have transformed our ability to visualise the fetus and to determine not only its structure but also its well-being. The collection of tissue from the developing placenta (chorionic villus sampling), fetal blood and other body fluids (urine, chest fluid etc) is also aided by ultrasonography - fetoscopy, which previously provided a vehicle for such sampling, is not now generally used.
Among the functional disorders which can be treated are:
The treatable metabolic disorders include:
Treatments to improve fetal condition include:
When couples understand that the cause of their problem is a change in just one of thousands of genes, they ask why the small piece of DNA in question cannot simply be changed. The Warnock Report of 1984 anticipated that this might become possible and recently a working cystic fibrosis gene in a mouse was replaced with a defective one.
Current methods of insertion cause genes to go into many different places in the genome - and yet they often work satisfactorily. It therefore appears that the controls must be in or around the gene. This gives hope that gene therapy might be possible.
In the vast majority of genetic diseases, especially autosomal recessives, parents are capable of producing normal children and it may be preferable in those cases to select an embryo (chosen by pre-implantation diagnosis) with the desired combination of genes.
The distinction between germ line and somatic cell therapy is an important one. If the fertilised egg is treated then the gene gets into all cells, including the gametes. Anything else is somatic gene therapy and it is necessary to get the gene into long lasting cells such as stem cells - treatment of short lived red blood cells, for example, is no better than a blood transfusion. Using antibodies to identify stem cells may be one means of hitting the right target.
Gene therapy may be particularly useful where the affected gene is on a mitochondrial chromosome, for example in certain kinds of diabetes. An embryo’s mitochondria and their chromosomes are inherited exclusively from its mother so that all children are likely to inherit affected maternal genes. A possible therapy is to replace the cytoplasm of the fertilised egg with that from the cell of a donor.
The recent Clothier report recommends that for the moment germ line gene therapy should not be allowed because embryo selection will give the same results; but the foregoing demonstrates that this is not always true.
Both mother and fetus have rights, if only in the sense that a duty to protect the interests of the fetus is a reflection of its rights. So, do the rights of the fetus in any way compromise the autonomy of the mother and the legal principle that the human body is protected against unconsented intervention?
The issue is likely to arise in two categories of case:
Under current UK law, the mother can do what she likes short of terminating her pregnancy by illegal means. But in the US there have been a number of decisions in favour of the fetus over the mother’s wishes - eg compulsory blood transfusions and Caesarean sections.
Dr McCall-Smith concluded that, in spite of the moral arguments in support of intervention, it is preferable to protect the right to maternal autonomy. If you accept that individuals can be forced to have treatment for the benefit of others, you are on a very slippery slope indeed.