According to a study reported in the American Journal of Obstetrics and Gynecology, twins conceived through in vitro fertilisation (IVF) are more likely to be born prematurely and delivered by Caesarean than those conceived through sexual intercourse.



Researchers at the University of Ottawa, Ontario, Canada compared 2,302 twins conceived through IVF and 2,326 twins conceived through sexual intercourse of women of similar age. IVF twins were 50 per cent more likely to be born prematurely and 33 per cent more likely to be delivered through a Caesarean than twins conceived naturally. However, there was no difference between the two groups in terms of low birth weight, stillbirths, serious complications during delivery or birth defects.



These findings come at a time when the UK's Human Fertilisation and Embryology Authority (HFEA) is to review its rules on how many embryos can be implanted during IVF treatments. Currently, over 90 per cent of IVF cycles in the UK involve transferring two or three embryos to increase the chances of success. However, this also leads to a greater chance of multiple births, which carry a larger risk for both the mother and the children, and costs the National Health Service (NHS) up to 10 times more. Now the HFEA has announced that it will consider limiting IVF treatments to the transfer of a single embryo per cycle, as has been done in some other European countries.



Two studies recently presented at the annual conference of the European Society of Human Reproduction and Embryology in Copenhagen also lend support to single embryo transfer (SET). The first study, performed by researchers at the Antwerp Centre for Reproductive Medicine, showed little difference between SET babies and those conceived naturally, in terms of birth weight, gestational age and proportion of still births. The only difference was that women who had undergone SET experienced more hypertension during pregnancy. The second study, performed at the University of Copenhagen, showed that singleton babies born after dual embryo transfer faced major health risks.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.