More than eight million IVF babies have been born in the last 40 years, researchers suggest.

Louise Brown became the world's first "test tube baby" when she was born at Oldham General Hospital in Manchester on July 25, 1978.

Since then, more than eight million babies have been delivered around the world as a result of IVF and other advanced fertility treatments, according to the International Committee for Monitoring Assisted Reproductive Technology (ICMART).

Half a million babies are now born every year from IVF and Intracytoplasmic Sperm Injection (ICSI) from more than two million treatment cycles, it is estimated.

The research is being presented at the European Society of Human Reproduction and Embryology (ESHRE) annual meeting in Barcelona.

Dr David Adamson, speaking on behalf of ICMART, said: "Based on ICMART's annual collection of global IVF data, it is estimated that since Louise Brown's birth in 1978 over eight million babies have been born from IVF around the world."

Commenting on the findings, Dr Gillian Lockwood, medical director at Midlands Fertility Services, said: "I think eight million is probably quite a conservative estimate because we know there's a huge amount of IVF going on in China and India that isn't necessarily reported, or recorded."

Spain saw the most treatment cycles for assisted reproduction in Europe with 119,875, according to the most recent data from 2015.

There were 110,723 cycles of IVF, ICSI and egg donation in Russia, 96,512 in Germany and 93,918 in France to treat infertility.

Data from the UK for 2015 was not available when European figures were compiled, but around 60,000 treatments are usually performed across the country every year, the researchers said.