Women in their late 30s and in their 40s are being given false hope that freezing their eggs gives them a good chance of having children, according to leading fertility experts.

The concerns come as thousands of women are believed to be considering “social freezing” – having eggs frozen for non-medical reasons as they grapple with declining fertility that could wreck any hope of a family later in life.

Some women going through the freezing, thawing and implantation process can pay as much as £15,000, with clinics claiming up to a 60% pregnancy rate. But a growing number of experts are becoming concerned that the regulator, the Human Fertilisation and Embryology Authority, isn’t doing enough to make it clear to women what their chances are of success really are.

Melanie Davies, an NHS fertility expert at University College London hospital, said: “10 years ago this was an experimental treatment, but as technology has advanced, egg freezing has now become routine. But women are still in the dark on success rates – over the next two years UK data should finally be coming out. Clinics and the regulator should make this available to help women make informed decisions.”

Adam Balen, chair of the British Fertility Society, told the Observer that women who are in their late 30s and in their 40s are being given “false hope” that freezing their eggs gives them a good chance of having children. “We have to be realistic about the prospects for success,” he says. “Essentially, the younger a woman is when she has her eggs frozen the more likely they are to survive, fertilise and achieve a pregnancy, but even then there is no guarantee.”

IVF pioneer Robert Winston, who has been vocal about this issue in the past, said: “The regulator 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. Some are massively overcharging and if you do this that would seem to be rather like exploitation.”

Soaring numbers of women are having eggs frozen for “social” reasons, some into their 40s. The number of eggs frozen in fertility clinics a year has almost tripled in recent years, according to latest figures from the HFEA. In 2008 there were 2,476 eggs frozen, rising to 7,047 in 2013, with the figure expected to have shot up since.

This dramatic rise is an indication that women are seizing an opportunity to try for children later in life, which they have perhaps been unable to do as they haven’t met the right person or are in a relationship in which they are not ready for children.

But growing interest in egg freezing has prompted a number of leading industry experts to express their concern over the way the industry is operating and how transparent it is about success rates.

Lord Winston says the industry is doing nothing to deter women who have little to no chance of success, primarily those in their 40s. “Doing this over 40 is much too late,” adds Winston. “The chances naturally with IVF at this age are only about 3-4%. 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.”

Official figures show that between 2008 and mid-2013 there were only 41 births from frozen eggs, or eight a year. Less than 2% of patients’ eggs thawed between 2008 and mid-2013 resulted in live births, according to analysis of HFEA figures. Of embyros transferred from frozen eggs that have been collected and fertilised, less than 13% led to a successful pregnancy.

Experts argue that these figures are pessimistic, as the HFEA doesn’t have the latest data available. A further uncertainty occurs because, while many women have frozen their eggs, few have so far returned to use them.

Clinics are keen to stress chances are much higher than claimed by some, particularly since the new flash-freezing “vitrification” process was introduced two years ago. This stops destructive ice crystals forming, meaning many more eggs survive the thawing process. However, Winston claims improved technology hasn’t necessarily increased the odds of success. “It’s colossally inefficient, with no evidence in spite of claims that it’s actually improving,” he says. According to Balen, the chances of eggs surviving the freezing and thawing process are around 70-80%, but it’s recommended that a woman freezes around 15 eggs for a reasonable chance of pregnancy, and many women will need to undergo multiple rounds of freezing to produce that many.

But Francoise Shenfield, a specialist in reproductive medicine and bioethics at University College London, says: “I believe it’s a good option for women who can afford the process, particularly given the average age of women giving birth for the first time in western Europe is creeping up. It’s around 30 now, which is a big jump in a generation.”

Despite recent press reports, Balen says he didn’t call for a women to have fertility “MOTs” at age 25 when they have their first smear test. However, he is keen to keen to raise awareness of the decline in fertility with age. He says: “In schools it is right to advise young people about safe sex and avoiding unwanted pregnancy, but also sow the seeds for the future about putting the family back into ‘family planning”, and when a bit older, for example at age 25, when women have their first smear, they should be told about how fertility declines and given advice about how best to plan for having a family.”

The HFEA says data on egg freezing will be introduced in the next Fertility Trends Report for the first time, expected to be released in January 2016.