The chances of giving birth to a healthy baby after in-vitro fertilisation are improved if just one embryo is implanted, researchers warned today.
Dr David McLernon of the University of Aberdeen, UK, and his team compared the effectiveness of planned single embryo transfer and double embryo transfer after fresh or frozen in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) treatment. They analysed figures from eight previous trials of 1,367 women.
The overall live birth rate for fresh IVF was lower after single than double embryo transfer (27 versus 42 per cent), as was the multiple birth rate (two versus 29 per cent).
But an additional frozen single embryo transfer led to a total live birth rate similar to one fresh double embryo transfer (38 per cent versus 42 per cent). This approach had a lower risk of multiple birth.
On the website of the British Medical Journal, the researchers report: "The odds of a term singleton birth after elective [planned] single embryo transfer was almost five times higher than the odds after double embryo transfer."
They write: "Although this strategy yields a lower pregnancy rate than a double embryo transfer in a fresh IVF cycle, this difference is almost completely overcome by an additional frozen single embryo transfer cycle."
The team recommends that clinicians base their advice to women on these findings.
In an editorial, Professor Allan Templeton of the University of Aberdeen, UK, warns: "In a commercially competitive environment, clinicians have been distracted by success rates and do not see the more important healthy outcomes. Doctors managing infertile couples are no longer entitled to take risks with the health of the next generation."
Templeton, A. Elective single versus double embryo transfer. The British Medical Journal, 2010;341:c7083.
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