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expert reaction to media reports that the frozen eggs of women awaiting fertility treatment may no longer be viable after a fault in freezing process

Scientists react to news that frozen eggs of women awaiting fertility treatment were damaged by faulty liquid at a London clinic. 


Prof Ying Cheong, Professor of Reproductive Medicine and Honorary Consultant in Reproductive Medicine and Surgery, University of Southampton, said:

  1. Egg freezing is increasingly popular; this rare but real incident sheds light on the importance of continued vigilance on the regulation of the cryopreservation processes including the use of cryoprotectants as any error in such processes are normally irreversible.
  2. The IVF laboratories utilises numerous types of products from media, consumables, cryoprotectants to hard and software; IVF centres in the UK are rigorously regulated to ensure traceability; this was an unfortunate case where the process of monitoring has failed, but there would be critical lessons learnt from this after investigation, to ensure it does not happen again.


Rachel Cutting, Director of Compliance and Information at the HFEA, said:

“The HFEA can confirm that this issue is limited to two clinics in the UK: Guys’ and St Thomas’ Assisted Conception Unit, London and Jessop Fertility, Sheffield.

“Our ongoing investigation only relates to Guys’ as we are satisfied that Jessop’s undertook a thorough investigation when they first became aware of the issue and contacted and supported any patient affected.

“The company supplying the product directly to clinics will know exactly where it’s gone through their traceability processes. The company is also obliged to report any problems to the MHRA.

“Any patients likely to have been affected will have been notified by their clinic. We hope this provides reassurance to anyone concerned.
“We share Field Safety Notices as required and every clinic is expected to act on the information provided. It is a legal requirement for clinics to report any incident to the HFEA in accordance with our clinical governance procedures, and in line with our Code of Practice.
“Fertility treatment in the UK is generally very safe, our most recent report shows that out of the almost 100,000 treatment and storage cycles which took place in 2022/23, more than 99% were conducted without any incidents occurring.
“As with any aspect of fertility treatment, more information on support can be found here.”


Sarah Norcross, Director of the Progress Educational Trust (PET), said:

‘It will be distressing for women with frozen eggs to learn that, due to problems outside their control, their eggs may not survive the thawing process.

‘When a woman freezes her eggs, time is of the essence. In all cases, the quality of eggs declines upon reaching a certain age. Additionally, in cases where women are freezing eggs for medical reasons – for example, imminent cancer treatment – they will not want their treatment to be delayed.

‘If women affected by this incident have undergone medical treatment which has compromised their fertility, then their opportunity to have a biologically related child may have been lost. If women affected by this incident had sought to extend their reproductive choices by freezing their eggs, then they too may have lost their best opportunity to have a family, if the quality of their eggs has declined during the period that has elapsed.

‘We still do not know all the details of why this incident occurred. Hopefully, further details will be forthcoming. What does seem clear is that there was an appalling delay of around a year between this problem being known about, and affected patients being notified. Apparently, there are also some patients with frozen embryos who are similarly affected.

‘We need to understand more about what precisely has gone wrong, whether patients at other clinics are affected, and what the relevant regulators – including the HFEA and the MHRA – are doing about it. We also need reassurance, from regulators and clinics alike, that processes are in place to notify patients in a timely way when things go wrong.’



Declared interests

Ying Cheong: No COIs

PET is a charity which improves choices for people affected by infertility and genetic conditions.

For all other experts, no reply to our request for DOIs was received.

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