Image copyright Science Photo Library Image caption Injected sperm fertilises the egg in Icsi, a type of IVF

Couples can find out their chances of having a baby over multiple cycles of IVF treatment, using a new online calculator.

University of Aberdeen researchers, who developed the tool, said it would help couples shape their expectations and plan their treatments.

The online calculator is based on data from more than 113,000 women who have gone through IVF.

A woman's age is the most important factor in her chances of having a baby.

After the age of 30, a couple's chances start to decline and keep on decreasing the longer the woman is unable to conceive.

There are other calculators that predict IVF success, but this is the first to give estimates for up to six IVF cycles and factor in the use of frozen embryos.

Predicting success

Couples can find out their chances both before and after their first IVF treatment - depending on the number of eggs that are collected, the health of the embryos transferred and the number of embryos collected for freezing.

Based on this information, a couples' chances can then be adjusted for further future cycles.

Fertility facts

one in six couples in the UK experiences problems conceiving

infertility in women is linked to age - the biggest decrease in fertility begins during the mid 30s

common causes of infertility in women include lack of regular ovulation, blockage of the fallopian tubes and endometriosis

but for 25% of couples, the cause of infertility is unexplained

in men, the most common cause of infertility is poor quality of semen

more than five million people had been born as a result of IVF or Icsi (intracytoplasmic sperm injection) by the end of 2013

David McLernon, research fellow in medical statistics at the University of Aberdeen, spent four years setting up the calculator using data from the Human Fertilisation and Embryology Authority, which collects information on all licensed fertility treatments in the UK.

He said the calculator should not be used by couples to decide whether or not they should have IVF treatment.

Instead, he said, it would help "keep them better informed and help them prepare emotionally and financially for their treatments".

And he said the tool could be used by clinicians, funders and policymakers too.

Mr McLernon's research in developing the calculator was not able to account take account of the woman's BMI, ethnicity, smoking status or alcohol intake in calculating IVF success - which can also affect fertility.

Susan Seenan, chief executive of patient charity Fertility Network UK said she hoped the calculator, which they helped develop, would help patients make more informed decisions about their fertility treatment.

But she added: "It is important to stress that the calculator should not be used in isolation. Anyone considering fertility treatment should discuss their individual chances of success with their clinician."

What is IVF?

In vitro fertilisation (IVF) is one of several techniques available to help couples with fertility problems have a baby.

During IVF, an egg is removed from the woman's ovaries and fertilised with sperm in a laboratory.

The fertilised egg, called an embryo, is then returned to the woman's womb to grow and develop.

It can be carried out using a woman's eggs and a man's sperm, or eggs and/or sperm from donors.