- In 2002, two proud and relieved parents, Mr and Mrs A,
saw their newborn twins for the first time, conceived after a long and
difficult course of IVF treatment. At last it all seemed worthwhile. Except
the babies were of mixed race, while both parents were white.
- The IVF clinic had blundered, and used the wrong sperm
to fertilise Mrs A's eggs. The child's biological father was Mr B, a man
the couple had never met and who with his partner was also trying for a
family using IVF. Similar accidents have happened in the US and the Netherlands.
- Now, in a bid to stop such mistakes happening again,
the UK's regulatory body, the Human Fertilisation and Embryology Authority
(HFEA) is considering labelling all embryos, eggs and sperm with barcodes
or electronic ID tags. The idea, discussed at the HFEA's annual conference
in London last month, is that an alarm will sound if the wrong eggs and
sperm are brought close to one another, for instance, or if a doctor attempts
to collect the wrong embryo to implant into a mother-to-be.
- In June 2004, an independent report commissioned by the
UK's chief medical officer suggested clinics use a system of double-witnessing,
which requires an embryologist to ask a colleague to witness and document
every procedure in which an error could occur. But with 25 such procedures
required for each round of IVF, the system is laborious. And it still leaves
room for human error.
- Sounding alarms
- Steve Troup, an embryologist on the HFEA's advisory group
on safety and new technologies, is looking into alternatives. Barcoding
has been used for more than a decade in the UK's blood transfusion service,
where it has slashed the error rate. Now IMT International, in Chester,
UK, is developing barcodes for IVF procedures.
- Digital cameras built into the IVF clinic's benches read
the barcodes off the bottom of labelled dishes containing eggs. A computer
then reads the codes, and sounds an alarm if they do not match with the
patient. "Our system is incredibly safe," says Tim Haywood, director
of IMT International.
- The electronic tags, known as RFID tags, work in a similar
way. They can be placed on the bottom of a dish containing an embryo, and
are activated by radio waves which transmit across a clinic's designated
work areas. When activated, RFID tags respond by transmitting a unique
ID code. "If the samples don't match [the patient], or you bring together
two things that shouldn't be in the same work area, the alarms will sound,"
- The HFEA is investigating whether such a system would
be safe, as there are concerns that radio waves might harm embryos. IVF
Witness, an RFID system being developed by Research Instruments, in Falmouth,
UK, has been tested on mouse embryos. The embryos are placed in Petri dishes
which have tags attached to the bottom, and placed in an incubator with
an antenna that activates the tags.
- Low frequency
- In Research Instruments' tests, the tags transmitted
continuously for four days without any perceptible effect on the embryos.
Though the tests are not complete, "it looks very, very good that
there's going to be no problem with it," David Lansdowne, technical
director at the company told New Scientist.
- Troup's personal view is that RFID tags will be safe
for in vitro procedures. The tags only transmit when activated by an external
signal. And they work at the low frequency of 13.5 megahertz compared with
900 to 1900 megahertz used by cellphones.
- The advisory group will need to be satisfied that such
an RFID system would not significantly heat up an embryo, or cause other
as-yet-unknown problems. Troup's research team at the University of Liverpool,
together with researchers at the University of Manchester, will be carrying
out more work looking at the effect of radio waves on mouse embryos. Lansdowne
says his team will be measuring the field strength from the RFID tags when
the embryos are being worked on, and comparing this with background levels
of radio waves.
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