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When you first visit the Unit to discuss your future treatment,
the Doctor will discuss with you the possibility of embryo freezing.
During IVF
or ICSI
, extra embryos may be produced. With your consent these
can be disposed of, or they may be frozen for your future treatment.
What is involved in embryo freezing
The freezing (also known as cryopreservation) of extra
embryos involves cooling them and storing them at very low temperatures.
This technique enables us to keep extra embryos as best
as we can.
What are the advantages of storing embryos?
The benefit of storing extra embryos is that you will
be able to undergo subsequent replacement of embryos without having
to undergo ovarian stimulation and egg collection.
What are the disadvantages of storing embryos?
Approximately 30 % of embryos do not survive the freeze-thaw process
and occasionally all the embryos from one patient may fail to survive.
Another disadvantage is that there is no guarantee that when the
embryos are replaced they will implant. Pregnancy rates are generally
less than those following fresh embryo transfer.
How long can embryos be stored for?
Embryos can be stored for years but the normal maximum statutory
period under the 1990 Human Fertilisation & Embryology Act is
five years. This storage period may be extended under the following
circumstances where the woman being treated, or her partner (if
he provided the sperm):-
(a) Is likely to develop significantly
impaired infertillity
(b) Carry a significant gene defect
(c) Become prematurely and
completely infertile
For (a) and (b),
the maximum statutory storage period depends upon the age of the
woman at the time the embryos were stored. If she is 45 years
or under at the time the embryos were first stored, the period is
10 years. However, if the woman is 46 years or over at the time
the embryos were stored, the period is determined by the date the
woman being treated becomes 55.
For (c) the maximum storage period
can be more than 10 years. However, supporting clinical judgement
must be provided in writing, by two doctors (one independent of
the unit) who are familiar with the woman and her treatment or partner,
their condition and medical history.
The man and the woman whose sperm and eggs were used to produce
the embryos must confirm in writing that they have no objection
to the embryos being stored for more than 5 years. In addition,
the embryos stored for longer than 5 years can only be used for
the purpose of providing treatment.
Other Things you Should Know
Safety
Although we will do our best to ensure the safe storage of your
embryos, we can not be held responsible for their safety or risk
of loss of embryos due to factors outside our control, such as equipment
failure. In addition, we can not guarantee that your embryos will
survive the freeze-thaw process or that a successful pregnancy will
result from their transfer.
Contact with the Unit
You must keep us informed of any changes in your circumstances e.g.
change of address. This is because we will need to contact you in
the near future to find out what you would like us to do with your
embryos as they reach the end of their statutory storage period.
If we are unable to contact you, your embryos will be destroyed
at the end of their statutory storage period.
Remember if you have any questions or concerns regarding embryo
freezing or any other aspect of your treatment, the staff at the
Unit are happy to help you.
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