ICSI does not improve IVF outcomes for non-severe male factor infertility

Intracytoplasmic sperm injection (ICSI) offers no advantage over conventional IVF in cases where men don't have severe male-factor infertility, a study has shown.

INVICSI, a Denmark-based randomised clinical trial, initially described in the British Medical Journal, measured cumulative live birth rates in ICSI and conventional IVF-treated couples where the man did not exhibit severe male-factor infertility. The results showed that ICSI did not improve the live birth rate compared with conventional IVF.

'Over recent decades, ICSI's popularity has surged, expanding beyond its initial scope to encompass two-thirds of all fresh fertility treatment cycles in Europe and globally', the authors from Copenhagen University Hospitals, wrote in their paper published in Nature Medicine. 'Its widespread adoption has prompted scrutiny into its extension to patients without male factor infertility', they added.

ICSI emerged in the 1990s as an IVF treatment option for cases of severe male-factor infertility, where sperm cells are directly injected into oocytes in vitro, overcoming such impediments to fertilisation, such as low motility or sperm count (see BioNews 1162). ICSI has increased in popularity, with ICSI used more than conventional IVF globally (see BioNews 1166).

However, this has prompted research, such as the INVICSI study, to definitively assess whether it offers any real benefit to prospective parents without severe male-factor infertility and can therefore be justified clinically (see BioNews 1226 and 730).

'The additional cost burden of ICSI compared to conventional IVF, often influenced by financial incentives, underscores the importance of robust, high-quality evidence to justify its use', the authors wrote.

INVICSI builds upon earlier randomised controlled trials, and one large retrospective study, conducted elsewhere, however, the researchers analysed data from 824 women whose male partners did not have severe male-factor infertility, in their first cycle of IVF, to give a clearer picture of the data.

The researchers focused on IVF methods, such as blastocyst transfer and elective single embryo transfer, to minimise the probability of multiple pregnancies. This allowed the use of cumulative live birth rates as the outcome measure, deemed the most robust standard for the success of fertility treatments. The research showed that the cumulative live birth rate for the ICSI group was not significantly different to the conventional IVF group.

The authors concluded: 'Given the substantial evidence from this and previous studies, it is imperative to reconsider the routine use of ICSI in patients without severe male factor infertility... treating couples without severe male factor infertility with ICSI over conventional IVF offers no benefits.'