Seed or soil: Cork’s pre-implantation genetic screening

The use of pre-implantation genetic screening (PGS) played a pivotal role in the successful IVF treatment for a 33-year-old Cork woman and her partner, who had a healthy baby girl at the end of October after a number of failed cycles.

Eight of their embryos were biopsied at the Cork Fertility Centre and then frozen. When analysis of the samples came back from a lab in Oxford, it showed only two were chromosomally normal, explains the centre's medical director, Dr John Waterstone.

“We thawed one of those two and put it into the mother and the other remains frozen. If they are lucky, they might have a sibling.”

The clinic recommends single transfer as although twin pregnancies “usually work out okay”, says Waterstone, they can deliver very prematurely, resulting in death or babies with significant problems.

He explains how there is a dichotomy between Europe and the US over the use of PGS. In the US “it is almost becoming a routine part of IVF treatment for couples who are struggling to have a baby, whereas in Europe we feel that is over the top”.

The Cork clinic is recommending it for a sub-section of IVF clients – those who have had multiple failures for no known reason. For those couples there is the fundamental question of “seed or soil”, he explains.

They want to know if the apparently healthy embryos that are being transferred are, in fact, perfect and it is the womb that is in some way attacking them, or are the embryos defective, so never stood a chance.

“There are clinics around the world who are pushing for all sorts of immune testing for couples who are struggling in this way,” he says. “These tests can be very expensive and usually don’t leave you very much wiser. To us, usually, where there are multiple failures, it is because the embryos aren’t good enough.” PGS gives a definitive answer on that.