New test for Down's syndrome introduced

Pregnant women across Lothian are being offered a new and more accurate screening test for Down's syndrome.

A small number of babies are born with Down's syndrome each year. The new screening test combines the results of a special ultrasound scan with a blood test. This is more accurate than the previous test at identifying the risk of a baby being born with Down's syndrome. Detection rates will increase from 60% (blood test alone) to at least 80% (combined test). The combined test is also expected to half the number of women being referred for further diagnostic tests such as an amniocentesis.

Women will be offered the screening when they are between 11 and 14 weeks pregnant. The special ultrasound scan, known as a 'Nuchal Translucency scan' measures the amount of fluid lying under the skin at the back of the baby's neck. This measurement and the results from the blood test are entered into a computer programme along with the women's age, weight and any other relevant factors to calculate the chance of the baby having Down's syndrome.

About 95% of screening tests will result in a 'low-chance' result. Women whose screening results show a 'high-chance' result will be given specialist advice from their midwife and will be offered the opportunity to have a diagnostic test. In most cases follow-up testing finds a healthy baby.

Dr Graham Mackenzie, consultant in public health, NHS Lothian, said:
"Screening can involve difficult choices and we want to make sure that we offer women the best services possible. This 'combined' screening is more accurate than the previous test and will reduce the need to offer women further diagnostic tests which increase the risk of miscarriage.

"The screening can only take place between 11 and 14 weeks so it is important that women tell us as soon as they know they are pregnant. The best way to do this is to call our maternity booking number - 0131 536 2009."

Pamela Hamilton, 31 from Edinburgh, is 14 weeks pregnant with her second child and has recently had the combined test. Pamela said: "Being pregnant is very exciting but there are worries. My husband and I chose to have this test so we could find out about the wellbeing of our baby and to prepare ourselves for all eventualities."

NHS Lothian is the largest health board in Scotland to offer this new service and has spent the past two years training ultrasound staff and establishing the new ultrasound and biochemistry tests. Following the introduction for women in Lothian, the new test will be rolled out across other east coast health boards. Samples from Fife, Tayside, Borders, Grampian, Orkney and Shetland health boards will be sent to NHS Lothian for analysis.

19/01/2011