Until now, approximately 40% of infertility cases have been linked to medical problems in men and 40% to medical problems in women, with the remaining 20% due to joint problems.
However, a report from the ESHRE committee that monitors assisted reproduction in Europe, has shown that ICSI (intracytoplasmic sperm injection) overtook conventional IVF techniques as the most commonly used assisted reproductive technology used in Europe in 2002.
There were more than 122,000 ICSI cycles and nearly 113,000 IVF cycles according to figures reported from 24 European countries in 2002. During the time that the committee has been collecting figures, the numbers of ICSI cycles have risen steadily: in 1997 the proportion of ICSI cycles versus IVF cycles was 43.7%; in 2002 it had grown to 52%.
Dr Anders Nyboe Andersen, Head of the Fertility Clinic at the Rigshospitalet at Copenhagen University Hospital, Denmark, and co-ordinator of the ESHRE IVF monitoring committee, said: "We do not really know why ICSI has become more prevalent. There are probably many reasons. One of them could be that the relative causes of infertility are shifting. We see less and less infertility caused by severe tubal problems in women, probably because of better sexual protection due to the risk of AIDS during the last 15 years. But male subfertility seems to be increasing. Perhaps the data on declining sperm quality are true, and maybe environmental factors are playing an increasing role as the planet becomes more polluted and factors that disrupt the endocrine system enter the food chain."
ICSI is a comparatively young assisted reproduction technique; it was developed by Gianpiero Palermo, with the first ICSI baby being born in 1992. Before its introduction traditional IVF required more than half a million sperm for a good chance of fertilisation; ICSI requires just one sperm to be injected into each egg. Sperm dysfunction may also be overcome by ICSI since more than 50% of eggs usually fertilise normally, regardless of the quality of the sperm injected, provided it is viable.
"It is also possible that as ICSI techniques have improved, patients and doctors are voting with their feet and using it in ever increasing numbers, despite any residual fears about its safety and the health of ICSI babies," said Dr Nyboe Andersen.
The quality and efficacy of assisted reproduction technology (ART) in Europe is steadily improving according the 2002 figures.
Chairman of the committee, Professor Karl Nygren, Associate Professor of Obstetrics and Gynaecology at Sofiahemmet Hospital in Stockholm, Sweden, said: "During the six year period from 1997 to 2002 there has been a minor decline in twin birth rates, and triplet birth rates have fallen from 3.6% to 1.3% after IVF and ICSI. For the first time we are seeing the impact of patients and doctors choosing to implant only one embryo [elective single embryo transfer - eSET], and in 70% of all transfers only one or two embryos were transferred. However, despite the reduction in the numbers of embryos transferred in one cycle, the pregnancy rate has remained the same or, in fact, in some countries actually improved.
"This is good news for mothers and babies, because multiple births are dangerous for both and can cause congenital problems in the offspring."
Dr Nyboe Andersen added: "New data from Finland and Sweden have demonstrated that single embryo transfer can be introduced on a national level without a decline in the ongoing pregnancy rate, but with a marked reduction in the multiple pregnancy rates. More than 50% of cycles in Finland and Sweden are single embryo transfer and the multiple delivery rate is approximately only 10% compared with about 25% in Europe as a whole."
Prof Nygren said: "Preliminary data emerging from Sweden for 2004 is even more exciting. Sweden banned transferring more than two embryos in 2003 and even before that date the number of single embryo transfers was increasing. The 2004 data show that 70% of all Swedish cycles were single embryo transfers, but the pregnancy rate per embryo transfer remained constant at around 30%, while the number of twin births has plummeted to just 5% and there were no triplet deliveries at all. In addition, the success rate of using frozen embryos has improved.
"These are really dramatic figures that show that single embryo transfer should be the first choice for young couples seeking fertility treatment."