First babies conceived with new IVF process

Three British women in their late 30s are due to give birth before Christmas after helping to pioneer a new IVF technique described as the "ultimate screening test".

Theirs are the first successful pregnancies in Europe to be achieved as a result of the procedure, which looks for abnormalities in cells taken from five-day-old embryos.

Blastocyst chromosome screening (BCS) can spot chromosomal mistakes in outwardly normal-looking embryos that may prevent pregnancies or lead to miscarriages. US evidence suggests the procedure can boost the chances of a viable pregnancy after in-vitro fertilisation from about 35 to 75 per cent.

The women are taking part in a year-long trial conducted by fertility specialist Care at its Manchester clinic. All three are aged between 37 and 40 and have a history of failed IVF.

BCS involves extracting up to ten cells from a specific part of the blastocyst, an embryo no larger than a pinhead. The cells are then analysed to check all their chromosomes - the cell structures that package DNA - for major abnormalities.

Only embryos that pass the test are implanted. A unique feature of the process is that it can tell whether the mother or father has passed on an abnormality by "cross-referencing" the embryo's chromosomes with those of the eggs and sperm.

Care specialist Dr Mark Sedler, who is leading the trial, said: "This is the ultimate screening test. We are getting ever closer to the perfect fertility cycle which gives the best chance of a single, healthy pregnancy."

He said embryos can be misleading. A perfect-looking blastocyst could conceal major abnormalities that would never allow a successful pregnancy. Conversely, an embryo with a poor-quality appearance may have excellent chromosomes.