Better Down's screening could be offered

A report published last week says that many pregnant women in Britain are not offered the best available screening test for Down's syndrome. The report, published in the British Medical Journal (BMJ), says that tests currently being used are less efficient, more costly and mean that more women than necessary are having further tests, such as amniocentesis, which can increase the risk of miscarriage.

The test most commonly offered is the 'double test', two types of blood test taken in the second trimester of pregnancy. The BMJ study rates this test as one of the least accurate or cost-efficient tests available. The highest ranked are two 'nuchal fold' tests which can be performed at around 12 weeks of pregnancy and only involve ultrasound. Different appearances in the folds at the back of the neck of a fetus can suggest an increased risk of Down's syndrome. The nuchal fold test was found to be effective when taken alone, and even more effective when taken in an 'integrated test' - in combination with four blood tests in the second trimester.

However, the study found that only seven per cent of women are offered the nuchal fold test, and only three per cent offered the integrated test. Dr Stuart Logan from the Institute of Child Health said that this type of screening would be more efficient, and therefore could save the NHS money; 'the double test fares poorly in our analysis - at no extra cost you could move to a better test'. He continued 'If you are going to offer people screening, you are doing it because you want to offer them choice, and give them the best information to make that choice'.

Meanwhile, a study to be published this week reports on a new test for Down's syndrome which, it is said, might also help prevent unnecessary amniocentesis. The test simply involves checking a particular nose bone during an ultrasound scan at about 12 weeks: those fetuses without the nose bone at this time are over 100 times more likely to have the condition.