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Some Down's markers 'more telling'

Tags: pregnancy

New research could make signs of Down's syndrome easier to spot in unborn babies.

A team of researchers has found that some markers for Down's syndrome are more telling than others when an ultrasound is carried out in a pregnant woman's second trimester.

According to scientists at King's College, signs such as dilated brain ventricles, an absent or small nose bone, and an increased thickness in the back of the neck are all potential markers for Down's syndrome.

The research, published in the Ultrasound in Obstetrics & Gynecology journal, also identified an abnormal artery to the upper extremities, bright spots in the heart, mild kidney swelling, and shortening of an arm bone or thigh bone, as potential warning signs.

To carry out the investigation, lead researcher Dr Kypros Nicolaides and his team looked at 48 previous studies published between 1995 and 2012 that looked at the results of second trimester markers for Down's syndrome. They found that most single markers have only a small effect on the chances of a child suffering from the disease.

This conclusion could have a clinical impact around the world, as in many countries, such as the US, women are told that their child is at increased risk of developing Down's syndrome if they show one marker such as a short arm or thigh bone in the ultrasound.

The researchers found that some markers do increase the chances of the development of Down's syndrome though.

The study showed dilated brain ventricles, increased thickness of the back of the neck, and an abnormal artery to the upper extremities can raise the chances of Down's syndrome by three-to four -fold. If an ultrasound shows the baby has absent or small nose bone, the chance of having Down's syndrome increased by six-or -seven-fold.

On the other hand, the baby is seven times less likely to have the disease if the second trimester ultrasound shows none of the major markers for Down's syndrome.

Prof. Nicolaides said: "The detection of any one of the findings during the scan should prompt the sonographer to look for all other markers or abnormalities."

Copyright Press Association 2013

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