Single embryo transfer fuels multiple birth debate

Katy Sinclair

Progress Educational Trust

24 June 2007

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[BioNews, London] Research into a new embryo transfer procedure has shown that many women having IVF could be treated with a single embryo without lowering their chance of conceiving a child. Yacoub Khalaf, of Guy's Hospital London, led the study into a new implantation technique, which involves growing embryos in culture for five days, rather than the usual three, before transfer. This allows embryos to become blastocysts, groups of 100 cells, which are more likely to implant. Blastocyst transfer is considered an appropriate method for women who can produce plenty of embryos, which accounts for about 20 per cent of IVF patients.

Mr Khalaf hopes that the discovery will reduce the multiple birth problem without affecting a patient's chances of starting a family. He said that, 'it is a myth that single embryo transfer has to lower the success rate. If you select the right patients, and use blastocyst transfer, it can be just as good'.

The common practice of implanting more than one embryo per cycle means that the chances of multiple births as a result of IVF are one in four, with multiple births being the single biggest health hazard of fertility treatment. The UK's HFEA (Human Fertilisation and Embryology Authority) estimated that last year 126 IVF babies died, who would have survived had they been single births. The HFEA is now debating whether to take disciplinary action against fertility clinics that produce twins or triplets in more than 10 per cent of pregnancies.

Meanwhile, in the US, two sets of sextuplets born within a day of each other have become headline news, with doctors emphasising that while the occurrence is rare, it does raise questions about the risks involved in multiple births. Brianna Morrison, from Arizona, gave birth to four boys and two girls on 10 June, after using fertility drugs to aid conception. Jenny Masche, from Minnesota, gave birth to three boys and three girls, conceived through artificial insemination, on 11 June. Dr F Sessions Cole, a paediatrics professor at Washington University in St Louis, commented that multiple births were 'something that we're going to be dealing with more and more'.

While all 12 babies remain in a stable condition, their births have raised questions over fertility treatment methods. Complications occurring with multiple births not only include premature birth and low birth weight, but additional pre and post-delivery complications. In response, doctors have recommended that fertility clinics review their methods in order to reduce the frequency of multiple births as a result of fertility treatment.

Reproduced with permission from BioNews, an email and online sources of news, information and comment on assisted reproduction and genetics.