A common procedure, known as endometrial or womb 'scratching', as an add-on to IVF has been shown to have no effect on pregnancy or birth rates.
Researchers who carried out a large international randomised clinical trial on womb scratching say that the procedure should be abandoned by fertility clinics.
'Results from earlier studies have suggested a benefit from endometrial scratching in IVF, especially in women with previous implantation failure,' said Dr Sarah Lensen at the University of Auckland, New Zealand. 'However, many of these studies had a high risk of bias in their design or conduct and did not provide strong evidence.'
The study involved more than 1300 women undergoing IVF at 13 fertility centres in five countries, including the UK. One half was randomly assigned to have an endometrial scratch, while the other half had no add-on procedure.
Both groups showed a similar pregnancy rate of 31 percent, and the same proportion of women – 26.1 percent – eventually had a baby in both groups.
The practice of endometrial scratching has 'become very widely adopted in international and UK practice', according to Mr Stuart Lavery, a consultant gynaecologist at Hammersmith Hospital in London, who was not involved in the study.
In previous studies that suggested a benefit, it had been proposed that causing a small injury to the womb's lining would result in an inflammatory response conducive to an embryo transplanting.
'Other trials have not been as big or as rigorous as this trial,' said Mr Lavery. 'It's one trial – but I think people might now pause and consider this.'
He added that the procedure is painful. 'If you are putting yourself through that you might want it to be of some degree of benefit.'
However, Professor Nick Macklon at the University of Southampton, said that many patients in the trial did not have a history of difficulty conceiving. 'It doesn't completely answer the question of the role of womb scratching in IVF.'
He added that the next phase would be to go back and see if there were any subgroups of women who might benefit. 'We have to be careful that we don't just write off a potentially useful intervention.'
However, he noted that the procedure 'probably has been overused'.
Dr Lensen presented the results of the trial at the European Society of Human Reproduction and Embryology annual conference in Barcelona, Spain.