Lord Winston, emeritus Professor of Fertility Studies at Imperial College London and pioneer of IVF, has criticised fertility clinics for over-hyping egg freezing services. In an interview with the Daily Mail newspaper he accuses providers of creating false optimism in the effectiveness of the procedure particularly where signing up patients for purely 'social' reasons. Before use of egg freezing grows further he calls for more research into both the effects of egg freezing on the ability to later conceive and into the long-term health implications for those born from frozen eggs.

The comments come in response to calls, made at last week's European Society for Human Reproduction and Embryology (ESHRE) annual conference, for greater availability of egg freezing as an option for women who are postponing pregnancy until later in their lives. Lord Winston's comments partially mirror a joint statement made in February by the UK's Royal College of Obstetricians and Gynaecologists and the British Fertility Society (BFS) which also called for women not to freeze eggs for social reasons.

Lord Winston noted that the production of six to ten eggs for freezing involves both the risk of ovarian hyperstimulation syndrome for the woman and an increased likelihood of chromosome defects in the eggs produced. Producing such a quantity of eggs he sees as dangerous yet also inadequate to ensure a viable embryo is produced. The BFS has stated that the average chance of success for any individual frozen egg is six per cent and only four children have been born from frozen eggs in the UK to date.

Additionally, the lack of data on the long term health effects - the first children conceived with frozen eggs are only now five - is provided as reason enough for adopting a cautious approach towards increasing availability of egg freezing and makes encouraging those without a pressing need (such as impending cancer treatment) all the more dubious. Lord Winston states, in unequivocal terms, 'in my view it is irresponsible [for clinics] to egg freeze until long-term animal research has been done'. The most detailed research to date is due to be published next month.

Describing the procedure as a 'quick fix', Lord Winston sees the best path forward for prolonging the ability to have a child, for social reasons, is to attempt to develop better means of postponing the menopause. Though the procedure can be justified for those with serious medical conditions it is not be encouraged as a means of delaying motherhood. The provision of egg freezing for social reasons, available for between £2,500 and £5,000 at 45 clinics in the UK, is in his view simply an 'undesirable commercial activity' and should not be encouraged.