The Freezing of Human Embryos

The Freezing of Human Embryos

It is twenty four years now since the first test-tube baby, Louise Browne, was born in England. The use of in-vitro fertilisation as a treatment for infertility has become fairly widespread since that time, and the procedure is on offer at a number of facilities in the Republic of Ireland. Strange as it may seem, although guidelines on some aspects of the practice of IVF have been approved by the Medical Council, there is no currently legislation in the Republic of Ireland to govern the generation and treatment of human embryos.

In-Vitro Fertilisation as a Treatment for Infertility:

Some years ago it was estimated that approximately ten per cent of couples were affected by infertility. The evidence suggests that this is on the increase.

I.V.F. and other related methods of assisted human reproduction are normally used to circumvent the problems caused by

· fallopian tubes which are blocked due to infection,

· endemetriosis (inflamation of the lining of the womb), or
the hostility to normally health sperm of the woman's cervical mucus.

The first stage in the I.V.F. procedure is the use of drug therapy to stimulate the ovaries, so that a significant number of ova can be harvested at the same time. It would not be uncommon for ten or eleven ova to be harvested. These ova are then fertilised in-vitro (in a glass dish). This usually results in the generation of a large number of embryos. It has been the practice over the years that, in order to avoid the risks of multiple pregnancy, no more than three embryos would be replaced in the womb. In more recent times, there seems to be a preference for using only two embryos, in order to minimise the risk of obsteteric complications.

In centres outside Ireland, surplus embryos are generally stored for future use by the couple. With the consent of the couple, they may be used for research purposes, or donated to other couples. After a fixed period, embryos in storage are generally disposed of by the “storage authority.” Readers will remember that thousands of embryos were disposed of in this manner in Britain some years ago. In Ireland, where there are very few centres offering IVF, the guide to ethical conduct, and to fitness to practice, published by the medical council in 1998, makes no provision for the storage of embryos, although it does deal with the storage of sperm and of ova. The disposal of embryos, or their use for research is specifically excluded.

Bending the Rules:

In the absence of embryo-storage in Ireland, it seems that the practice developed over a period of time of replacing surplus embryos outside the uterine cavity. Such a practice is, to all intents and purposes, the same as the disposal of embryos. It might appear to be in keeping with the letter of the ethical guidelines, but it would certainly contrary to their spirit. (An Irish solution to an Irish problem?)

Against this background, it is possible to understand why reputable obstetricians have argued in favour of the freezing and storage of embryos, which they would say is preferable to the charade of replacing them in such a way that they cannot survive. While this may appear to be a better solution, it is not acceptable, because it immediately gives rise to the problem of how these stored embryos should be treated, who should exercise control over them, and what should be done with them when they are no longer wanted.

The Human Embryo:

At this point it is useful to consider briefly the nature of the human embryo. The embryo could be described as the product of human fertilisation. It is not simply raw material. It is a distinct human entity. Developments in genetic science help us to realise this, because it is now possible to see that the embryo has it’s own genetic identity, which is distinct from the genetic pattern of either of the parents, though related to them. Even in the case of monozygotic (identical) twins, there is ample evidence to suggest that, while the division of the cell mass may not appear until as late as fifteen days, the twinning is genetically based, and therefore has its origins at the time of fertilisation. A Select Committee of the Australian Senate, reporting in 1986, describes the embryo as “ genetically human” and as an entity (a centrally organised unit which has a purposeful independent function, as opposed to an organ or tissues).” The report explains that the term embryo is used deliberately “to speak of new human life, organised as a distinct entity orientated towards further development.”[1]

Recent embryological studies indicate that fertilisation is a process rather than an instantaneous event. This process, it is argued, is only complete when cell division begins. The stage prior to cell division is described as the pronuclear stage, and lasts a number of hours. The question has been raised as to whether the human pronucleus ought to be treated differently from the embryo which exists after fertilisation has been completed.

When the sperm and the ovum come into contact, and the protective membranes are penetrated,

the parts of the plasmalemma of the spermatozoon and the egg, outside the zone of contact, fuse together in a continuous sheet. The cytoplasmic contents of the two gametes are now in direct continuity. Although the shape of the spermatozoon may yet be distinguishable, the two gametes have at this stage become one single cell. [2]

The pronucleus is already clearly far more than a sperm cell and an ovum. It has an organic unity and is, as one unit, oriented towards on-going development. It is also, of course, biologically human. At most, therefore, science can tell us that there exists a doubt as to when exactly the biological product of human fertilisation begins to subsist as a distinct entity. As long as that doubt exists, it is unethical to destroy what may well be a person.

It is worth noting that it has been possible to successfully freeze both sperm cells and the human pro-nucleus itself, but it was only in mid 2002 that researchers indicated that they had succeeded in achieving an on-going pregnancy using a frozen ovum. This is sufficient evidence to demonstrate that, by the pro-nuclear stage, the fusion of the gametes in the metazoa has already activated the ovum and significantly transformed it. The organism is complete; it has already begun to develop. Its development is not complete, of course, nor will it ever be, until the organism dies.

I.V.F. is Ethically Flawed from it’s Origins:

Depending on how it is carried out, In-Vitro Fertilisation and Embryo Transfer may be grossly abusive of the human embryo, or it may be relatively less so. The ethical problems associated with I.V.F. are so rooted in its very nature, however, that it is very difficult to provide it effectively without going down a path which is destructive and debasing to the human embryo.

Research

There is much information to be gained from research on human embryos; in particular information about the causes of genetic malformations. It is important, however, to ensure that such research is carried out in a way which respects the life and dignity of the embryo. Human embryos must never be treated simply as a means to an end. The Declaration of Helsinki requires that if it is proposed to carry out experimental procedures involving human subjects, their consent must be first be obtained. Where the person concerned lacks the capacity to give informed consent (e.g., when the person is unconscious, or mentally handicapped), consent may be given by the next of kin, but only for procedures which are likely to be of therapeutic benefit to the person concerned. In the case of human embryos who are clearly not competent to give informed consent, destructive research is routinely carried out in flagrant disregard of this fundamental ethical principle. In Ireland, embryo research is prohibited by the Guide to Ethical Conduct and to Fitness to Practice. The fact remains, however, that I.V.F., as practiced in Ireland, is dependent on research that is going on elsewhere, and will continue to be dependent on this research in the future. This is something which has been acknowledged by Mary Warnock, who headed the British government commission on human embryology.

Using multiple embryos

The practice of using more than one embryo in each treatment cycle is generally accepted, three being the number which has traditionally been considered to be safe and effective. Where three embryos are used, the success rate in terms of pregnancies achieved may be up to 25%. In terms of live births, the success rate is of the order of 10 - 15%. This, of course, reflects an embryo survival rate of 5% or less. Where only one embryo is used, the success rate is significantly lower (at about 10%), but this reflects a significantly higher rate of survival of the individual embryo. It is worth noting, therefore, that the procedure which offers the best chance of a successful pregnancy also exposes each individual embryo to a proportionately greater risk. [3]

Super-ovulation leads to the demand for storage

Super-ovulation (the harvesting of ova in large numbers, following drug therapy) is common practice. While, theoretically, this need not require that large numbers of embryos be generated, the normal practice seems to be that all the ova harvested are fertilised. This gives rise to a dilemma; either the surplus embryos have to be stored by cryopreservation, or they must be disposed of in some other way. It would seem, therefore, that the decision to generate more embryos than can be used in any one treatment cycle is a key issue from an ethical point of view.

The Personalistic Implications of I.V.F.

The human embryo is far more than simply a commodity, even a very valuable one. It is not appropriate, therefore, that human embryos should be exposed to the fluctuations of supply and demand, as other consumer products in the market place. Where a process akin to manufacturing is used for human reproduction, the temptation inevitably arises to engage in quality control at some level. This is clearly the case in the current practice of I.V.F. in many countries, where good embryos are selected and defective ones rejected.

Informed Consent:

Undoubtedly couples whose infertility is treated by I.V.F. are primarily concerned with having a child. Infertility can be a source of considerable stress in a marriage. What is not always recognised is that the disappointment of repeated unsuccessful attempts at IVF can also be a source of stress, not to mention economic pressure. An essential part of helping couples to respond positively and constructively to infertility is to ensure that they are fully informed as to the implications and consequences of I.V.F. both for the embryo, and for themselves as a couple.