Women in their late 30s and 40s so they can have children later are being given false hope, according to leading fertility experts.

Thousands of women across the country are believed to be considering ‘social freezing’ – having eggs frozen for non-medical reasons – as an option to extend the time they have before starting a family.

Around 600 British women a year pay up to £30,000 to freeze their eggs until they want to start a family, as an insurance measure against their declining fertility.

Clinics encourage women, who do not yet consider themselves ready for children, by claiming a pregnancy rate of up to 60 per cent.

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'False hope': Experts claim that women are being given false hope, and not being warned how low their chances of having a baby from frozen eggs really are. Pictured, embryos (fertilised eggs) frozen in liquid nitrogen

But an increasing number of experts are concerned that the fertility watchdog, the Human Fertilisation and Embryology Authority (HFEA), is not making it clear enough to women what their chances of getting pregnant really are.

‘The regulator [HFEA] keeps itself at arm’s length, making no serious attempt to control the vast fees charged, or take any control over the claims made by private clinics,’ IVF pioneer Robert Winston told The Observer.

‘Some are massively overcharging and if you do this that would seem to be rather like exploitation.’

He added: ‘Doing this over 40 is much too late. The chances naturally with IVF at this age are only about three to four per cent.

‘But there are massive profits to be made with clinics playing on women’s fears and encouraging them to have two or more cycles – on top of vast sums for egg storage.’

Expert: Lord Robert Winston (pictured), who pioneered IVF, said that there are 'massive profits to be made with clinics playing on women's fears and encouraging them to have two or more cycles - on top of vast sums for egg storage'

Information from private clinics shows that interest in egg freezing is increasing in some parts of the country by up to 400 per cent a year – with some women in their late teens and early 20s considering the procedure.

Dr Sue Avery, director of Birmingham Women’s Fertility Centre, said that the risks and benefits of different techniques should be made clear to any prospective mother.

‘It is very important that women who are freezing their own eggs for future use are property counselled.

‘There is no guarantee that we are going to have an embryo transfer, let alone a birth. It is extremely important that women have the proper information.’

Adam Balen, chair of the British Fertility Society, added that women ‘have to be realistic about the prospects for success’.

Technology: But clinics claim that the most recent figures are misleading and obsolete. They claim that technologies have improved in the last two years, and the chances of having a baby are far higher. Pictured, embryos selected for IVF

Younger audience: Information from private clinics shows that interest in egg freezing is increasing in some parts of the country by up to 400 per cent a year – with some women in their late teens and early 20s considering the procedure. Pictured, a visualisation of IVF procedure

In 2008, there were 2,476 eggs frozen according to the latest figures released by the HFEA. By 2013, that figure had risen to 7,047. It is expected to have risen dramatically since then.

In the five-year period between 2008 and 2013, however, there were only 41 births from frozen eggs.

Clinics claim, however, that technologies have vastly improved in the past two years, leading to better success rates.

One of these improvements is the introduction of the flash-freezing ‘vitrification’ process. It is said to stop destructive ice crystals forming, meaning more eggs survive the thawing process.