Non-invasive Early Pregnancy Screening: Can Reduce Down Syndrome Births?

Filed in archive Cases , Diagnostics on June 18, 2007

In Denmark, non-invasive screening of pregnant women (early in the pregnancy, 11 to 14 weeks of gestation) with ultrasound combined with maternal blood analysis, has reduced the number of children born with Down syndrome by 50%.

The combined screening is measurement of nuchal translucency in the fetus by ultrasound - to look at the thickness of the black space (fluid) in the neck area of the fetus (more than the normal amount of fluid means increased risk of down syndrome) and a certain combination of serum markers in the maternal blood test (taken at the same time) -to determine the possibility of an increased risk of a chromosomal abnormality.

And then those women, whose test results showed an elevated risk of Down syndrome were offered an invasive procedure called chorionic villus sampling or amniocentesis to definitely confirm or exclude the diagnosis of Down syndrome by chromosome analysis.

Professor Karen Brøndum-Nielsen of the Kennedy Institute (Glostrup, Denmark) has presented these findings last Saturday (June 16) at the ongoing annual conference of the European Society of Human Genetics in Nice, France.

According to Dr. Brøndum-Nielsen:

"Previously this was restricted to pregnant women over 35 years of age, but since the implementation of the new guidelines it has been available to any woman who wants it.

When we looked further at the history of children born with Down Syndrome, we found that their mothers had declined the offer of screening, or had taken it up too late in pregnancy.

Although we have not yet studied the whole of the population, these numbers are significant enough to show that the new guidelines have been accepted by a great majority of Danish parents.

However, there is a need for analysis of the psychosocial aspects, both as to the pre-test counselling and the women´s attitudes."

Administration of the procedure above has decreased the birth of babies born with Down syndrome by 50%, while the claimed additional benefit of the introduction of this procedure in Denmark was a drop in the number of invasive pre-natal diagnostic procedures from 11% to approx. 6% of pregnancies.

If I would read between the lines of what is being stated here, what did the scientists do when a woman is diagnosed confirming the Down syndrome of her unborn child? Will the fetus be treated to correct the condition or will she be advised to have abortion? Because either of these two scenarios can explain the 50% reduction in babies born with Down syndrome. The screening procedure was just the tool.

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