A couple trying for a baby using in-vitro fertilisation (IVF) can now get a personalised prediction of the likely outcome of their treatment in just several clicks of a mouse by using the simple online calculator at ivfpredict.com.

After answering a series of nine questions about the couple’s medical history and previous IVF attempts, the predicted success of their treatment is then displayed as a percentage. But the simplicity of the calculator’s front end belies the complexity of what is going on behind the scenes.

Professors Lawlor and Nelson analysed the details of more than 144,000 IVF cycles to produce the statistical model which powers the calculator giving a highly accurate prediction of live birth.

Using data from the Human Fertilisation and Embryology Authority, the researchers looked at all cycles carried out between 2003 and 2007 and assessed the chances of having a live birth. As Debbie Lawlor, Professor of Epidemiology from the University of Bristol puts it: “The sheer scale of the data which we analysed is the key to the accuracy of this model. The more data you look at, the more accurate the predictions become.”

IVF treatment is an expensive and stressful option which is only successful in about a third of women under 35 years old decreasing to five to ten per cent of women over the age of 40.

Historically, a woman’s age was often the major factor used by clinicians to counsel prospective IVF couples. But age is not the only indicator which significantly affects the outcome and by providing additional information about the couple’s medical history the calculator’s novel prediction model produces a significantly more accurate picture for the couple.

Professor Scott Nelson, from the University of Glasgow says, “Up until now estimates of success have not been reliable. The result of this study is a tool which can be used to make incredibly accurate predictions.”

One couple undergoing IVF treatment said that, "we were considering donor eggs and IVFpredict helped us make a difficult choice." Another patient described the tool as, "fantastic and simple to use, [it] helped me decide to continue with IVF."

Professor Lawlor also says that, “The IVF calculator is not only of use to the couples themselves but also to health care funders like the NHS to ensure appropriate use of resources”, making this a valuable tool, especially in the prevailing climate of public spending cuts. The calculator is now also available as an iPhone app and is due to be released for Android phones soon.

Professor Gordon Smith, Head of the Department of Obstetrics and Gynaecology at Cambridge University welcomed the findings saying that “There is a real need in medicine to try and replace general statements such as ‘high risk’ and ‘good chance’ with well validated, quantitative estimates of probability.

"This model for predicting the outcome of IVF has exploited a valuable collection of routinely collected data, applies sophisticated statistical modelling and the output provides people considering IVF with an understandable and quantitative estimate of their chances of success. It is a great resource.”