Growing evidence suggests that miscarriage and failed implantation in IVF may largely be due to chromosomal abnormalities in the developing embryo. Studies show beyond doubt that this rate of abnormality increases with female age. It’s for this reason that the incidence of chromosomal conditions in babies - such as Down’s syndrome - also increases with the mother’s age. Find out more about the effect of female age on pregnancy.
Modern techniques of chromosome screening can test embryos and identify those which are chromosomally normal in the hope that their transfer will maximise the chance of pregnancy. The latest techniques of embryo screening use a method known as ‘next generation sequencing’. All chromosomes can be assessed and only embryos identified at low risk of chromosome abnormalities are selected for embryo transfer.
These same advanced techniques of genetic analysis make it possible to screen eggs and embryos for specific abnormalities. The basic technique - pre- implantation genetic diagnosis, or PGD - was successfully introduced more than 20 years ago. It was designed to detect genetic alterations in the embryos of couples known to be at risk of passing on inherited disease to their children. These were usually fertile couples, whose only need of IVF was to provide a number of embryos for analysis from which a few might be ‘diagnosed’ as unaffected. Any couple with a record of genetic abnormality in a previous pregnancy would be advised to consider PGD. There are many conditions - some very rare, some, like cystic fibrosis, more common - which can be detected in embryos.
PGD provides an alternative to prenatal testing by CVS or amniocentesis - and thus prevents termination at a later stage of pregnancy.
The London Women's Clinic is able to provide a full range of embryo screening services.