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The 14-day limit should be extended to 28 days

15 February 2021
By Sophia McCully
MSc Bioethics and Society student, King's College London
Appeared in BioNews 1083

The '14-day rule', initially proposed in 1979 in the USA, was first recommended in the UK by the Warnock Committee in 1984. It limits research on intact human embryos to 'prior to 14 days' gestation or the beginning of primitive streak formation' and is part of the Human Fertilisation and Embryology Acts of 1990 and 2008 (HFE Acts).

This legislation has been successfully implemented in the UK, but also in several other countries (eg, Australia's Research Involving Human Embryos Act 2002). It is followed in jurisdictions without relevant laws or even guidelines. While researchers accepted the rule, and have been content to keep to it, many contend that it was simply an arbitrary time limit that was chosen as a compromise to authorise any research at a time when pro-life views were strong. While originally it was a barrier that could not be breached for practical reasons, recent research on human and non-human primate embryos suggest that we now have methods to culture intact human embryos beyond 14 days.

I recently argued, in the Journal of Medical Ethics, that the current limit for embryo research should be extended to 28 days to permit research that will further explore our origins as well as potentially provide new therapeutic possibilities to reduce developmental abnormalities and miscarriage.

This conversation is something the Progress Educational Trust (PET), the charity which publishes BioNews, has been advocating for many years. Recent work they have accomplished includes a proposal to the 'My Science Inquiry' launched by the House of Commons Science and Technology Committee. Sandy Starr, deputy director of PET gave oral evidence to the committee advocating for this conversation to be had by government, as it is already an ongoing debate within the scientific community. PET also held their annual conference in 2016, which focused on the 14-day limit on human embryo research, and that featured Baroness Mary Warnock, who was chair of the committee that originally proposed the limit in 1984.

There are a number of reasons why research on embryos between 14 and 28 days, often referred to as the 'black box' period of development, is now ready to be initiated. Several of these are emphasised in my paper.

Firstly, the 'black box' period is when the basic body plan and the formation of critical cell types, tissues, and some organs is initiated. These include germ cells, which are not only essential for the next generation, but are also the early progenitors of the nervous system, blood cells and the heart, and the placenta. It is known that even a subtle defect can have a devastating effect on subsequent development. While we know something about how these develop in model organisms such as the mouse, there are clear differences with human embryos, making it difficult to infer results between species. We also can't yet rely on new stem cell-based models of early human embryos without first carrying out detailed comparisons with the real thing.  

It could be argued that 28 days is not long enough. Whilst this is certainly a thought-provoking point, we are already able to obtain embryonic tissues from 28 days and beyond and older fetal tissue to use in scientific research eg, from an aborted fetus. It is also important to consider the need for a 'limit'. If there is not one at all, there is no compromise, discontent, and it could complicate the regulatory system.

In conversations surrounding the 14-day limit there are differing ethical opinions. I argue that in order for those trying for a baby to have legitimate reproductive autonomy, they should have the appropriate assistance and opportunity to produce, at the very least, a healthy child. I also focus on the need to differentiate between 'research' embryos and 'reproductive implanted embryos' ie, the research embryos in question are those whose location will remain in a petri dish.

It is absolutely crucial to outline the importance of a robust regulatory body. In the UK, we are lucky to have the Human Fertilisation and Embryology Authority (HFEA), which means there is government oversight making sure fertility clinics and research centres comply with the law, this extends to human embryo research. For example, in 2016, Dr Kathy Niakan was not just the first person in the UK to be granted a license from the HFEA to use genome editing techniques on human embryos, but the first anywhere to have this type of research sanctioned by a regulatory body. (See BioNews 835).

With any significant legislative change that will directly impact the population, significant public debate must be instigated. Public opinion must be widely surveyed and considered, because any decisions like this should not just be one made by a select few individuals. This can be seen with another significant change in the HFE Act, the addition of mitochondrial donation regulations in 2015, which is an example where public engagement was very important. It gave the Government license to make the changes in the HFE Acts, knowing that there was broad support for the use of the methods to avoid mitochondrial disease.

As I conclude in the paper, just because something has once worked does not mean it should stay the same or not strive to be improved. The 14-day limit has become limiting and the conversation around extension must continue.

The time has come to extend the 14-day limit
Journal of Medical Ethics |  5 February 2021
7 June 2021 - by Dr Sigal Klipstein 
The first IVF baby was born in 1978, and represented a milestone at the cross section of basic science, clinical research and patient care...
1 June 2021 - by Sandy Starr 
The International Society for Stem Cell Research has published wide-ranging new guidelines, covering a number of contentious areas of research and clinical practice...
26 April 2021 - by Dr Patrick Foong 
Is an international conversation on the 14-day rule needed in the light of the development of iBlastoids?...
12 April 2021 - by Beatrice Costa 
Should research on human embryos be permitted beyond 14 days?...
8 March 2021 - by Amarpreet Kaur 
The Human Fertilisation and Embryology (HFE) Act 1990 is the UK's legislation regulating the storage and use of human eggs, sperm and embryos...
30 April 2018 - by Shaoni Bhattacharya 
Almost 34 years ago, Baroness Mary Warnock headed up a committee whose report was to form the basis for the legislation and regulation of IVF and embryo research the world over...
6 February 2017 - by Dr Ciara Staunton 
Some have suggested that, after Brexit, British influence on rules about embryo research will be diluted. But this is far from true...
9 January 2017 - by Baroness Mary Warnock 
As the Progress Educational Trust's Patron, Baroness Mary Warnock, is made a Companion of Honour in the New Year Honours List 2017, she offers her thoughts on whether the 14-day limit on human embryo research (which she originally proposed in 1984) should be extended...
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