DNA test replaces amniocentesis at Valladolid hospital

Expectant mothers have the option of undergoing an amniocentesis, which involves extracting fluid from the amniotic sac which protects the baby before it is born and which enables medics to test for genetic or chromosomal disorders such as Down's Syndrome, especially if the mum has a family history of conditions such as cystic fibrosis, muscular dystrophy, sickle cell disease, or has already had a child with Down's or another hereditary health problem.

Although the risk is extremely low – less than 1% - an amniocentesis can lead to miscarriage or infection, particularly if it is carried out before the 15^th week of the pregnancy.

The Río Hortega University Hospital in Valladolid, in the centre-northern region of Castilla y León, has now developed a way of testing DNA without any risk to either the mum or the baby.

Regional government spokeswoman Milagros Marcos says a cash injection of €1.15 million has enabled the hospital to purchase the materials needed.

The procedure involves an ordinary blood test, with the sample tested for aneuploid cells, since the DNA of the foetus is present in the mother's blood.

And medics at the Río Hortega say not only is the process easier with no danger of miscarriage, but the results are even more reliable than those of an amniocentesis.

Sometimes, an error in the amniocentesis procedure or an unclear result can lead to its having to be repeated, increasing the discomfort for the mother and also putting her, yet again, through the fear of the test causing her to lose the baby.

How it works

All human cells, except red blood and sex cells, contain 23 matching pairs of chromosomes and are referred to as 'euploid cells', but if an extra chromosome is present, or one is missing, leaving an odd number of these in the cell, these are called 'aneuploid cells' and typically result in disorders such as Down's Syndrome.

This said, recent research on mice has shown that embryos with up to 50% of cells being aneuploid were still, in some cases, able to give birth to healthy offspring – the defective cells were sometimes found to 'self-destruct', allowing normal ones to carry on developing as they should as the embryo evolved.

The Cambridge University-based study, the results of which were published in March last year, may be a double-edged sword for high-risk mothers, particularly pregnant women over 40 – any abnormalities detected through amniocentesis or DNA testing cannot be corrected, meaning the mother may face the tough decision as to whether or not to carry on with the pregnancy, a dilemma made even more difficult by the possibility of a healthy baby being born despite defective results.