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ANTENATAL SCREENING FOR DOWN'S SYNDROME AND NEONATAL SCREENING FOR PHENYLKETONURIA (PKU) AND CONGENITAL HYPOTHYROIDISM

Background

1. The UK National Screening Committee (NSC) advises the UK Health Departments about the introduction of new population screening programmes, the modification or withdrawal of existing programmes and the quality and management of such programmes. The Committee has recently recommended the introduction of more organised screening for a wide range of antenatal/neonatal conditions including Down's Syndrome, and PKU/Congenital Hypothyroidism. Down's Syndrome is a congenital condition that is associated with moderate to severe learning disability and a spectrum of other health problems. The current birth prevalence is estimated to be 1.3/1.8 per 1,000 live births and increases with increasing maternal age. PKU and Congenital Hypothyroidism are inherited metabolical disorders, which, if left untreated, lead to significant learning disability in affected children. The Minister for Health and Community Care has accepted the Committee's recommendation to improve the organisation of Antenatal Screening for Down's Syndrome and neural tube defects and the screening of babies for PKU/Congenital Hypothyroidism and that the Screening Programmes should be implemented to agreed UK standards within appropriate management frameworks.

2. This guidance outlines the action proposed to organise screening for Down's Syndrome and neural tube defects and PKU/Congenital Hypothyroidism more effectively and for Health Boards to develop audit programmes to ensure the effective operation of the services and that relevant interventions or treatments are implemented quickly and effectively.

Down's Syndrome

3. As at present, all pregnant women should be offered serum screening for Down's Syndrome in the second trimester of pregnancy. This screening test aims to identify women who are at increased risk of having a baby with Down's Syndrome and who should be offered a definitive diagnostic test such as amniocentesis or chorionic villus sampling. These diagnostic tests are invasive procedures which can diagnose Down's Syndrome in pregnancy but carry a small risk of foetal loss. The purpose, benefits, and possible outcomes of such screening should be explained to women when the screening test is offered and, women/parents should be offered the opportunity to discuss the options available to them, should a positive diagnosis be made. One option which may be offered is termination of the pregnancy, however women may wish to proceed with the pregnancy in the full knowledge of the risks to the baby. This is a sensitive issue and women should be given comprehensive and unbiased information to enable them to make informed choices. Women have the right to choose whether or not to have the initial test, the diagnostic test and their preferred option if the screening diagnosis is positive on the clear understanding that they may opt out of the screening process at any stage.

4. While screening for Down's Syndrome is already offered to all pregnant women in all Health Board areas in Scotland, and there is a well organised and high quality service in place with a number of effective working arrangements in maternity units, there is however a lack of co-ordination across Scotland. There is also a need to improve training for midwives and other staff, audit and information flows between obstetric units, the laboratories, the women and primary care. To ensure a more effective screening process, the Scottish Screening Programmes' Central Co-ordinating Unit has been commissioned to co-ordinate and monitor the Down's Syndrome Screening Programme using quality standards which will be derived from those recommended by the National Screening Committee. In particular, the Central Co-ordinating Unit will be responsible for establishing and supporting the following infrastructure:

5. Health Boards and Trusts are required to appoint designated co-ordinators to ensure the delivery of effective screening services for Down's Syndrome and neural tube defects in their area. The co-ordinators will meet with the Central Co-ordinating Unit regularly to discuss the Programme and review monitoring data. They will also be called on to help to facilitate the implementation of an appropriate infra-structure to support a co-ordinated antenatal screening programme within their Health Board and to facilitate the implementation of further screening programmes in the antenatal period as further advice and recommendations come forward from the NSC.

PKU/Congenital Hypothyroidism

6. PKU and Congenital Hypothyroidism can be detected in the first few days of life by simple tests which can be done on dried blood spots (Guthrie Test). Early detection and treatment (dietary restriction in PKU and thyroid hormone replacement in CHT) can prevent severe intellectual impairment. While new born babies throughout the UK have been screened for PKU and Congenital Hypothyroidism for the last 20 years, there has been no quality standards or framework in place for the Service as a whole. The Scottish Screening Programmes' Central Co-ordinating Unit has been commissioned to co-ordinate and monitor the PKU/Congenital Hypothyroidism Screening Programme and will be responsible for establishing and supporting the appropriate infrastructure, including the introduction of a training scheme for staff involved in testing and supporting patients. The training scheme and infrastructure will be similar to that proposed for the Antenatal Screening Programme for Down's Syndrome. The Central Co-ordinating Unit will also be working with appropriate groups of healthcare workers to establish a managed clinical network to enhance the clinical care and follow-up of children in Scotland with inherited metabolic disease, most of whom will have been detected through the screening programme.

7. It is expected that the arrangements for the Screening Programmes will be implemented with effect from 1 April 2002.

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