A second study suggests that ICSI may not even have benefits over IVF more generally, when it comes to the birth of babies resulting from treatment.
Both studies were presented at the annual conference of the European Society for Human Reproduction and Embryology in Vienna, Austria.
'Based on the results of our study there is no advantage of ICSI over IVF in the case of non-male factor infertility,' said Dr Panagiotis Drakopoulos from UZ Brussel in Brussels, Belgium, a centre which pioneered the ICSI technique.
Their study also investigated whether a woman's response to ovarian stimulation in order to obtain eggs had any bearing on the success rate of each procedure in cases of male infertility. They found none.
'The number of oocytes retrieved should not play any role in the selection of procedure,' Dr Drakopoulos told delegates. 'So please, do not give ICSI to poor responders.'
The study by Dr Drakopoulos and colleagues retrospectively analysed data on 4891 patients from 15 hospitals across Europe. Of these, some 4227 patients were treated with ICSI and 664 with IVF.
The researchers found no difference in fertilisation rates or live birth rates (including cumulative live birth rates) achieved using each method.
The second study, presented by Dr Hajeb Kamali from the Bristol Centre for Reproductive Medicine in the UK, found no difference – in Human Fertilisation and Embryology Authority (HFEA) data spanning the years 2000-2016 – between live birth rates achieved with each method.
The study looked at 224,021 first cycle treatments in women under 40, half of whom had ICSI and half of whom had IVF. Although ICSI seemed to give better fertilisation rates than IVF, the outcome in terms of babies born was no different.
ICSI was originally developed to treat severe male factor infertility, but is now used more widely in situations where male fertility may not be the issue. 'Over the last decade the use of ICSI has dramatically increased,' said Dr Drakopoulos.
He added: 'In some countries the use of ICSI is sixty times higher than use of IVF.'
Dr Drakopoulos noted that as well as making no difference to outcomes where male infertility was not implicated in couples undergoing IVF, ICSI also carried an added financial cost.
'The bottom line – I think that we have overestimated the effect of ICSI – and actually we have arrived in a situation of therapeutic illusion,' he said.