A technique that is best known for its use in cancer genetics is being hailed as a step towards dramatic improvements in the success of IVF treatments.

“The holy grail for us is one egg, one embryo, one baby, and this gets us closer to that holy grail”, said Simon Fishel of the CARE fertility clinic in Nottingham, UK. His comments relate to a study by Geoffrey Sher and Levent Keskintepe of the Sher Institute for Reproductive Medicine in Las Vegas, USA, who have used comparative genomic hybridization (CGH) to screen IVF embryos for aneuploidies (Daily Mail, 31 January 2007).

As reported in the journal Fertility and Sterility, Sher and Keskintepe developed the CGH-based method as an alternative to using fluorescence in situ hybridization (FISH), which fails to recognize abnormalities in 13 out of 23 pairs of human chromosomes. Using the technique, out of 35 women who were implanted with screened embryos, 28 became pregnant, with 18 successful births so far and 8 more expected shortly. “This is a projected live birth rate of 74% — more than twice the average for IVF,” says Sher (New Scientist, 30 January 2007).

Other fertility experts have urged caution until the CGH method has been tested in a larger study group. However, if validated, this approach could significantly reduce the emotional heartache and financial headache that often goes with IVF treatment, especially in countries where there are limits on the number of embryos that can be implanted. As explained by Fishel, who is now testing the method in the United Kingdom: “At least half of a couple's embryos have a chromosome abnormality. The problem is that if you have lots of embryos and we're only allowed to put two back, you don't know which two to choose” (The Guardian, 1 February 2007).