Health Evidence Bulletins - Wales

The contents of this bulletin are likely to be valid for approximately one year, by which time significantly new research evidence may have become available

Appendix: Statistical Information Sources and Audit

The purpose of clinical information is in the assessment and analysis of health status and needs of the population served, outcome measures and the application of resources. The importance and the relative paucity of maternal and perinatal data have been stressed by several influential groups(1-3). 1. Clinical Standards Advisory Group. Women in normal labour. Report of a CSAG Committee. Tindall VR (Chair). London: HMSO, 1995;
2. Department of Health and Others. Report on Confidential Enquiries into Maternal Deaths in the United Kingdom. 1991-1993. London: HMSO, 1996
3. Departments of Health. National Advisory Body. Confidential enquiry into stillbirths and deaths in infancy. Annual report for 1 January - 31 December 1993. Part II. London: Department of Health, 1996;
Data on every registrable birth to women resident in Wales is currently available from the Welsh Office and the Office of National Statistics (ONS, previously OPCS). The ONS publishes data taken from birth notifications and registration of deaths relating to district of residence, including outcome and birthweight4. Both the Welsh Office and ONS publish other useful summary information(5-9) 4. Office for National Statistics. Monitor Population and Health. DH3 - Annual Publications. London: Office for National Statistics;
5. Office for National Statistics. Key Population and Vital Statistics: Local and Health Authority Areas. 1996; Mortality Statistics. See 4.;
6. Central Statistical Office. Annual Abstracts of Statistics. London: HMSO;
7. Office for National Statistics. Regional Trends. See 4.;
8. Botting B, Crawley R. The health of our children. Dicennial supplement. London: HMSO, 1995;
9. Government Statistical Services. Health Statistics Wales. Cardiff: Welsh Office, 1995;


Birth notification initiates a child’s record on the Child Health Computer Database. The Child Health System (CHS), established in 1977 to manage the childhood immunisation and vaccination programme, also collects data on child health surveillance and for children with special needs(10). There are plans to upgrade the system to make the valuable data it contains more easily accessible to all professional users. It has been shown to be capable, even on its current configuration, of producing a minimal maternity and perinatal data set for Wales. 10. Welsh Health Common Services Authority. Report on maternity data/information aspects of the Child Health Data System. Cardiff: WCHSA, 1996;
Detailed analysis on mortality is available through reports on maternal deaths2 and the All Wales Perinatal Survey(11) and CESDI(3) which report a detailed analysis of all fetal and infant deaths from 20 weeks gestation to 1 year of age. 11. Cartlidge PHT. All Wales perinatal survey and confidential enquiry into stillbirths and deaths in infancy. Annual Report 1995. Cardiff: Welsh Office, 1996
Denominator and morbidity data are more difficult to obtain. The Patient Episode Database for Wales (PEDW) provides only limited information on hospital episodes(12) as do the National and Welsh Morbidity Studies of General Practice activity(13-14). 12. WCHSA Information Group. Patient Episode Database for Wales. Cardiff: WCHSA, 1996;
13. McCormick A, OPCS. Morbidity Statistics from General Practice. Fourth National Study 1991-1992 London: Office of Population Censuses and Surveys, 1995;
14. Rogers C, Evans E. Personal Communication regarding the General Practice Morbidity Database;


Other local or limited data sets do exist, or are being developed, and may be taken as models for other developments:
  1. All Wales Congenital Anomaly Service - a register of all congenital anomalies and of ante-natal screening used in diagnosis - to be linked with the existing Eurocat register and with the ONS congenital abnormality register(15-16).
  2. Audit of Cerebral Palsy Wales(17).
  3. Follow up of preterm infants (1500 g or less). The importance of this study relates to both the high investment of resources and the potential for handicap among these children. This problem has been reviewed by a working group of the NPEU(18-21).
  4. Sudden Infant Death: Wales has been part of the case ascertainment of the national CESDI study.
  5. Detailed population based maternity/perinatal data are currently available in parts of Wales, in West and South Glamorgan and in West Wales. Each of these Trusts are in the process of revising or upgrading their computer platforms.
15. OPCS. Working Group of Registrar General’s Advisory Committee. Chair: Professor Alberman. The OPCS monitoring scheme for congenital malformations: a review by a working group of the Registrar General’s Medical Advisory Group. Occasional paper No. 43 London: Office of Population Censuses and Surveys, 1995;
16. Cotter M, Elder S, Lawrence M. Wales’ participation in the Eurocat surveillance of congenital malformations. Cardiff: WCHSA, 1996
17. Penny L, Sibert J. Audit of cerebral palsy for children in Wales. Final Report. December 1994;
18. National Perinatal Epidemiology Unit, Working Groups convened by NPEU and Oxford Regional Health Authority. Disability and perinatal care - measurement of health status at two years. Oxford: NPEU, March 1994;
19. Cartlidge PHT, Stewart JH. Survival of very low birthweight and very preterm infants in a geographically defined population. Acta Paediatrics. 1997; 86: 105-110.
20. Tin W, Wariyau U, Hey E, Northern Neonatal Network. Changing prognosis for babies of less than 28 weeks gestation in the North of England between 1983 and 1994. British Medical Journal 1997; 314: 107-111;
21. Escobar GJ, Littenberg B, Petitti DB. Outcome among surviving very low birth weight infants: a meta-analysis. Archives of Disease in Childhood. 1991; 66: 204-211


Certain principles relate to all data collection(22):
  • It must have relevance to those who provide the information and should, wherever possible, be obtained as a by-product of clinical, operational IT systems.
  • It must be timely
  • It must be population based - This is especially relevant in the field of maternity and perinatal care where changing practice and more emphasis on home based care, require ongoing assessment
  • It must be complete to prevent bias
  • Data sources should use common definitions
  • It should be possible to transfer information between systems
22. Accepted good practice; and see Mason A, Morrison V. Walk don’t run. A collection of essays on information issues published to honour Mrs Edith Krner CBE; Chairman of the NHS/DHSS Health Service Information Steering Group 1980-1984. London: King Edward’s Hospital Fund, 1985
Recommendations for audit in maternity care are summarised in a document from the Royal College of Obstetricians and Gynaecologists Clinical Audit Unit(23). 23. Benbow A, Semple D, Maresh M. Royal College of Obstetricians and Gynaecologists Clinical Audit Unit. Effective procedures in maternity care suitable for audit. London: Royal College of Obstetricians and Gynaecologists, June 1997.

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Health Evidence Bulletins: Wales, Duthie Library, UWCM, Cardiff CF14 4XN. e-mail: