'Wide variations' in worldwide frozen embryo transfer [Updated]
Dr Vivienne Raper
Progress Educational Trust11 January 2010
Frozen embryo transfer (FET) remains rarely used in Australia, New Zealand and Africa, according to a recent survey. Just 8.3 per cent of IVF (in vitro fertilisation) procedures in Australia and New Zealand use embryos frozen after a previous cycle of IVF, the IVF-Worldwide survey of 179 IVF centres in 56 countries found.
Rates in Africa are also low - just 5.3 per cent of IVF procedures involve FET. These figures compare poorly to Europe and the US and Canada where, respectively, 33.4 per cent and 26.6 per cent of IVF cycles involve FET.
The survey was conducted by IVF-Worldwide.com - an online directory of IVF centres. The commissioners of the survey believe that the cause of the global differences may be that 'it takes a lot of time, effort and expertise to build a successful cryopreservation program'.
FET is a relatively non-invasive fertility treatment because it uses embryos left over following an IVF cycle. Instead of being destroyed, these spare embryos are frozen for later thawing and transfer. IVF-Worldwide says FET is 'widely practiced' as a 'safe and cost-effective method to increase cumulative pregnancy rates'.
The FET survey, which covers 133,290 IVF cycles including 39,152 using FET, highlights other differences in practice between continents. For example, centres were divided over how they prepared patients who regularly ovulated for FET. Almost half (49 per cent) used FET during a hormonally-supported cycle, while the other half (45 per cent) delivered it during the patient's natural cycle. Approaches to monitoring patients, and determining when to thaw embryos or deliver FET also varied widely.
IVF-Worldwide says these differences to 'a large extent reflect lack of solid and evidenced-based data in this field'.
"In BioNews 540 (last week), we reported that 'just 8.3 per cent of IVF (in vitro fertilisation) procedures in Australia and New Zealand use embryos frozen after a previous cycle of IVF'.
This statistic was based on a pie chart issued by IVF-Worldwide, which we have since been informed is incorrect and which has now been removed from the IVF-Worldwide website. From a table in the IVF-Worldwide survey, the correct figure for Australia and New Zealand is 38.9 per cent.
The updated survey results are available online at the link below."
Reproduced with permission from BioNews, an email and online sources of news, information and comment on assisted reproduction and genetics.