London, July 7 : Researchers from Italy have shown that infertile men can more than double their chances of fatherhood with a new IVF technique called intra-cytoplasmic morphologically-selected sperm injection (IMSI).
The method, which was first developed in 2004 by a team led by Benjamin Bartoov, of BarIlan University in Israel, involves examining sperm under a high-magnification microscope, about five times more powerful than standard laboratory equipment, to select those with a shape and size that indicates good genetic quality.
The best-looking sperm are then injected into eggs.
The treatment builds on the success of intra-cytoplasmic sperm injection (ICSI), a therapy for male infertility that has enabled thousands to become fathers since it was developed in the early Nineties.
ICSI involves fertilizing an egg in a laboratory by injecting it with a single sperm.
As the sperm does not have to swim up to the egg and penetrate it, the method can help men whose sperm would otherwise be too weak.
Even when men produce no sperm, doctors can sometimes recover them surgically from the testes.
The team of Italian researchers, led by Monica Antinori, of the Raprui clinic in Rome, conducted the largest randomized controlled trial to compare outcomes for IMSI and ICSI.
The study involved 446 couples in which the man was infertile and the woman was not known to have any problems.
The results showed that the IMSI method could deliver considerable improvements in pregnancy rate.
The overall pregnancy rate for the IMSI group was 39.2 per cent, compared with 26.5 per cent for the ICSI patients.
Among men with the worst prognosis, who had had at least two failed attempts at ICSI before, the improvement was better still.
The pregnancy rate for IMSI was 29.8 per cent, compared with 12.9 per cent for standard ICSI. The miscarriage rate also fell considerably.
The results are encouraging for men with an especially poor fertility prognosis and who have tried and failed to have children by IVF in the past.
"By treating this kind of patient with this technique, we offer them an opportunity to solve their fertility problems. As you can see from the results, the group that has had two or more IVF failures can get more than twice the opportunity to have a pregnancy with this new technique," Times Online quoted Antinori, as saying.
The study is published in the journal Reproductive Biomedicine Online.