Professor Scott Nelson, a researcher from Glasgow University, said: ‘The test provides critical information on the likely outcome for couples deciding whether to undergo IVF – up until now estimates of success have not been reliable.
‘Not every attempt at IVF is successful.
‘In the U.S. and the UK, IVF is successful in about a third of women under 35 years old but in only 5 to 10 per cent of women over 40.
‘However, there are many other factors in addition to age which can alter your chance of success and clinics don’t usually take these into account when counselling couples or women.’ Fertility treatment can cost between £3,000 and £15,000 per course. But fewer than one in four IVF treatments leads to a birth.
Although other calculators exist, they are either less accurate or involve such intricate data about subjects such as hormone levels that they can only been done in a doctor’s surgery.
Debbie Lawlor, professor of epidemiology at the University of Bristol, said: ‘The IVF calculator is not only of use to the couples themselves but also to health care funders such as the NHS to ensure appropriate use of resources.
‘The sheer scale of the data we analysed is the key to the accuracy of this model. The more data you look at, the more accurate the predictions become.’
But Professor Bill Ledger, a leading fertility doctor and member of the fertility watchdog, the Human Fertilisation and Embryology Authority, urged caution.
He said: ‘While the test will give an individual some idea of their chances, it is not much use unless put alongside data from the clinic the woman attends.’
Some clinics have much higher – or lower – success rates than others, he said. The test is available at ivfpredict.com