Embryo Freezing and Frozen Embryo Transfer (FET)

After a fresh embryo transfer, good quality surplus embryos and blastocysts created during IVF or ICSI treatment may be frozen and stored for future use. Embryos can be stored at an extremely low temperature (-196˚C) to suspend their development. Once frozen, they can remain in liquid nitrogen for many years without deterioration before being thawed and, if they survive and subsequently develop well, transferred to the woman’s uterus during a frozen embryo transfer (FET).

Freezing good quality embryos offers a chance of conceiving after an unsuccessful fresh embryo transfer, or even several years following a successful transfer and pregnancy.

To be suitable to freeze, embryos must:

be at the correct developmental stage for the number of days the embryos have been cultured; for example two days after fertilisation an embryo should be four cells
contain cells which are approximately the same size which indicates regular division
contain less than 25% fragmentation
have well defined cellular membranes indicating that they are not undergoing a delicate cellular division at that precise moment

Using thawed frozen embryos gives the possibility of a brother or sister for a patient’s baby from a single cycle of IVF or ICSI treatment - known as a conceptual twin.

Legislation determines the time that MFS, with patients’ consent, is allowed to store embryos. This is currently up to five years, but may be extended to ten years or more in certain circumstances. Some MFS patients have had babies more than ten years after their embryos were originally created and frozen.

Where other clinics may charge an additional fee for embryo storage, the cost of embryo freezing and one year’s storage at MFS is included in the fees for all IVF and ICSI treatments at MFS.

MFS contacts patients every year to make sure they still wish the clinic to continue storing their embryos and so it is vital that the clinic has a correct address while embryos remain in storage. When the consented period of embryo storage ends, MFS is legally obliged to remove the embryos from storage unless the patient has contacted MFS and the storage period has been extended.

Who may benefit from embryo freezing?

couples who achieve many good quality embryos following egg collection and fertilisation which can be stored for possible future attempts to conceive
a woman in a relationship about to undergo medical treatment that may make her infertile in the future can have embryos created and frozen before the treatment to give her the chance of having children with her current partner, at a later date
patients who have had an egg collection for IVF or ICSI treatment, who have been advised not to go ahead with a fresh embryo transfer will have their embryos frozen for use in treatment at a later date

What does FET treatment involve?

most frozen/thawed embryos are replaced in the uterus which has been prepared using hormone replacement therapy (HRT), to improve the chance of a successful outcome
where HRT is not recommended for medical reasons, the clinical team may suggest transferring the frozen/thawed embryos in a natural cycle to eliminate the need to take hormone medication
depending on the number of frozen embryos and the result of the last embryo transfer, the embryologist may recommend allowing the thawed embryos to develop to blastocyst stage before transfer
before embryos can be frozen, both partners will be asked to complete a form to consent to the storage of the embryos, as required by the HFEA. This consent can be altered or withdrawn at any time if the patients’ circumstances change, for example if a couple separates. If one partner decides to withdraw consent to storage or use of embryos, MFS has a legal obligation to inform the other partner that the embryos will be removed from storage
it is essential that both partners advise MFS immediately of any change in their circumstances or their address while embryos remain in storage

What is included in the cost of a FET?

The initial cost of embryo freezing and one year’s storage is included in the original IVF or ICSI treatment fee. The cost for a FET includes:

monitoring ultrasound scans
thawing and monitoring of embryos in the lab
embryo transfer
pregnancy test and scan and/or follow-up to review the treatment cycle

What is not included in the cost of a FET?

follow-up consultation (as appropriate)
repeat screening (as appropriate)
IVF or ICSI treatment including egg collection
cost of fertility drugs, eg hormone drugs
the HFEA levy for the transfer of embryos

How long does treatment take?

An average of five to eight weeks from the beginning of the treatment cycle to pregnancy test.

Costs

Cost of egg retrieval using IVF and embryo freezing: £2,600

Cost of egg retrieval using ICSI and embryo freezing: £3,100

NB The initial cost of embryo freezing and one year’s storage is included in the above treatment fees

Cost of annual embryo storage at MFS: £155

Cost of FET at MFS: £990