Ten years of monitoring ART in Europe sees a doubling of cycles and higher pregnancy rates, with fewer embryos transferred and fewer multiple births
ESHRE01 July 2009
Amsterdam, The Netherlands: Twin deliveries after assisted reproductive technology (ART) have fallen below 20% for the first time in Europe according to the tenth report summarising data on ART in Europe, which was presented at the 25th annual meeting of the European Society of Human Reproduction and Embryology in Amsterdam today (Wednesday).
In the year 2006, the most recent year for which figures are available, 19.9% of all ART deliveries were twins, 0.9% were triplets and, for the first time, there were no quadruplet deliveries; 79% of all ART deliveries were singletons. Ten years earlier, in 1997, the first year for which ESHRE started collecting data, singleton deliveries were 70.4%, twins 25.8%, triplets 3.6% and quadruplets 0.15%.
Professor Anders Nyboe Andersen, chairman of ESHRE’s European IVF monitoring consortium, said: “The good news is that we are continuing to make improvements in the quality, safety and efficacy of ART. For the first time, European ART twin deliveries are below 20%. Fewer embryos are being transferred to women’s wombs but there are better pregnancy rates throughout Europe.
“During the ten years that ESHRE has been monitoring ART in Europe we have seen a decline in the overall multiple birth rates from 29.5% to 20.8%, and a more than four-fold reduction in triplet and quadruplet births from 3.7% to 0.9%. Meanwhile pregnancy rates have continued to improve and in 2006 the average pregnancy rate per embryo transfer in Europe was 32.8% after IVF, 33.6% after ICSI*, 21.6% after frozen embryo transfer and 43.5% after oocyte donation. This compares with 26.1% after IVF, 26.4% after ICSI, 15.2% after frozen embryo transfer and 27.1% after oocyte donation in 1997.”
However, he pointed out that several countries were still transferring four or more embryos per ART cycle: in 2006, 1.6% of all transfers involved four or more embryos per transfer.
“Foetal reduction remains a major cause of the low triplet rate,” he said. “In 2006, 471 foetal reductions were reported in Europe and this corresponds to 0.8% of deliveries after the transfer of fresh (as opposed to frozen-thawed) embryos after IVF or ICSI. Therefore, the 0.9% triplet rate for 2006 is much lower than it would have been without foetal reduction.”
Certain countries, mainly in Eastern Europe, had a high proportion of three and four embryo transfers and a similarly high proportion of foetal reductions. For instance, Bulgaria reported 60.8% three or four embryo transfers after IVF and ICSI and, of the resulting deliveries, 7.6% involved foetal reduction; Ukraine reported 60.3% three or four embryo transfers and, of the resulting deliveries, 7.4% involved foetal reduction.
The consortium collected data from 32 countries in 2006. Ninety-two per cent of all the clinics in these countries (1020 out of 1110) reported data. In 21 countries, 100% of clinics reported data, while a proportion of clinics reported data in the other 11 countries.
Since 2005 there has been a 3% increase in the number of reported cycles, rising from 419,037 to 429,948 in 2006. The number of cycles in 2006 was more than double the 1997 figure of 203,225 cycles. Countries carrying out the largest number of cycles in 2006 were France (65,404 cycles), Germany (54,695), Spain (50,476) and the UK (44,101). The Netherlands carried out 17,770 cycles.
The availability of ART was highest in Denmark (2,337 cycles per million inhabitants), Belgium (2,187 per million), Iceland (1,793 per million), Finland (1,721 per million) and Sweden (1,631). In The Netherlands it was 1,084 cycles per million and in the UK, 729 cycles per million.
Prof Nyboe Andersen said: “The rise in the use of ICSI in preference to IVF continues. The number of ICSI cycles rose to 233,823, while IVF cycles dropped to 116,827. ICSI now accounts for 66.7% of all ART procedures, while standard IVF accounts for 33.3%. Ten years ago it was exactly the opposite. There is no obvious reason why this should be so, as the efficacy of ICSI in terms of pregnancy rates is the same as standard IVF. There are major differences between countries. Some, like Spain and Turkey, almost exclusively use ICSI, whereas IVF remains the dominant technology in Scandinavia, The Netherlands and the United Kingdom. These major differences can only be caused by variations in professional preferences from one country to another. There is no available scientific evidence that these high utilisation rates of ICSI are beneficial – especially considering that this technology is more time-consuming and expensive and only gives a higher pregnancy rate in couples with severe male infertility.”
Apart from multiple births, another complication of ART can be ovarian hyperstimulation syndrome (OHSS). In 2006, 27 of the 32 countries contributed data on OHSS, and out of 260,764 cycles involving hormonal stimulation in these countries there were 2,753 cases of OHSS – an incidence of 1.1%, which is similar to the incidence of 1.2% in 2005. “This suggests that there is no significant increased use of milder stimulation protocols in Europe at present,” said Prof Nyboe Andersen.
Professor Jacques de Mouzon, chairman of the International Committee for Monitoring Assisted Reproductive Technology (ICMART), reported preliminary data on world ART to the conference on Wednesday morning.