National Congenital Anomaly System Research Articles

A new national data collection for congenital anomalies in England and Wales

AimIn 2009 the National Congenital Anomaly System (NCAS) run by the Office for National Statistics (ONS) ceased data collection. In 2011, the Department of Health funded the British Isles Network...

Ascertainment and accuracy of Down syndrome cases reported in congenital anomaly registers in England and Wales

Objective:Congenital anomaly registers allow the rates of anomalies to be monitored and are essential for understanding their epidemiology. We estimate the ascertainment and accuracy of records of Down syndrome (DS)...

Regional congenital anomaly registers in the UK

Regional congenital anomaly registers, while monitoring fewer than 50% of births in England and Wales, contribute almost 80% of the annual data entered into the National Congenital Anomaly System, with a notification rate over four times that from non-register areas. They employ multiple sources of ascertainment, producing high-quality data. This contrasts sharply with known deficiencies in a national system largely dependent on birth notifications. Details of anomalies in pre-24-week gestation deliveries and antenatal soft markers are unavailable from any other source. Members of the British Isles Network of Congenital Anomaly Registers contribute data to national, European and worldwide anomaly surveillance systems, pooling data on rare anomalies for research and providing valuable information for counselling, clinical management and audit. However, large areas of the UK remain outside register coverage, and most existing registers depend on precarious funding. Despite their acknowledged value, their long-term future is far from secure.

Prevalence of hypospadias in the same geographic region as ascertained by three different registries

Hypospadias birth prevalence may be increasing with maternal exposure to endocrine disrupters. Yet hypospadias registers are hindered by data quality concerns. We compare the birth prevalence per thousand male births (BP) and ascertainment of hypospadias in the South East of England between 1st January 1997 to 31st September 1998 in a population-based hypospadias case register (surgeons' register) 731 cases, BP 3.8, (95% confidence interval 3.7-3.9), the National Congenital Anomaly System (NCAS) 645 cases (88% of surgeons' register), BP 3.4, (95% confidence interval 3.29-3.5) and Hospital Episode Statistics (HES) 221 cases (30% of the surgeons register), BP 1.15 (95% confidence interval 1.1-1.2). There were 191,438 male births (National Statistics). We found considerable differences in birth prevalence estimates and ascertainment according to data source. Compared with the Surgeons' register, the HES under-ascertainment of 10% was possibly explained by procedural weaknesses. NCAS's 70% under-ascertainment is explained by exclusion of so-called mild hypospadias (since 1990). This exclusion does not appear warranted since mild and severe hypospadias probably share aetiology and all require surgery. NCAR's utility could be improved if it returned to including "minor" hypospadias. Meanwhile routine data such as HES are potentially suitable for surveillance of this condition.

Evaluation of the general practice research database congenital heart defects prevalence: Comparison to United Kingdom national systems

As part of an effort to validate the General Practice Research Database (GPRD) for future studies of medication use in pregnancy, this study examined whether the rates of all, and specific types of, congenital heart defects obtained from the GPRD are similar to those obtained from UK national systems. The prevalence rates of heart defects for 2001-2003 were determined from the GPRD and compared with both the National Congenital Anomaly System (NCAS) and the European Concerted Action of Congenital Anomalies and Twins (EUROCAT). Rate ratios (RRs) and 95% CIs were calculated comparing the prevalence of all congenital heart defects as well as specific types of heart defects in the three data sources. In addition, the effect of the child's age on the frequency of heart defects in the GPRD was determined. The prevalence of heart defects in the GPRD was more than twice as high as in the NCAS and slightly higher than in the EUROCAT. All differences were statistically significant. The prevalence of specific heart defects varied across the GPRD, NCAS, and EUROCAT. The measured prevalence of congenital heart defects in the GPRD was higher if calculated including children up to age 6. The comparisons of the GPRD prevalence rates to national prevalence estimates demonstrate that the GPRD can serve as a more complete source of background prevalence for the most commonly occurring congenital heart defects, which is essential to properly assess possible associations between maternal exposures and congenital heart defects.

Congenital anomaly surveillance in England and Wales

The National Congenital Anomaly System (NCAS) was set up in 1964, following the thalidomide epidemic, as a monitoring system designed to detect changes in the frequency of reporting of malformations. Its original aim was to detect anomalies reported within 7 days of birth. The NCAS is voluntary at all stages and covers all live- and stillbirths. It has two tiers; a 'passive system' receiving congenital anomaly notifications through a standard paper notification form, known as the SD56, and the congenital anomaly registers that send notifications electronically. Congenital anomalies are classified using the International Classification of Diseases codes and 10 monitoring groups. The Office for National Statistics performs a statistical analysis on a monthly, quarterly and annual basis, using the cumulative sum technique, which is the basis upon which surveillance alerts are raised within the system. The NCAS is now an open database where congenital anomalies can be notified whenever they are detected. The aim of this paper is to describe the current operation and uses of the NCAS based on guidelines for the evaluation of public health surveillance systems published by the Centers for Disease Control and Prevention.

Evaluation of the National Congenital Anomaly System in England and Wales

Objective: To evaluate the National Congenital Anomaly System (NCAS). Methods: The NCAS in England and Wales based at the Office for National Statistics and the various regional registers that exchange...

Congenital anomaly surveillance in England—ascertainment deficiencies in the national system

Objective Firstly, to assess the completeness of ascertainment in the National Congenital Anomaly System (NCAS), the basis for congenital anomaly surveillance in England and Wales, and its variation by defect,...

Toward the effective surveillance of hypospadias.

Concern about apparent increases in the prevalence of hypospadias--a congenital male reproductive-tract abnormality--in the 1960s to 1980s and the possible connection to increasing exposures to endocrine-disrupting chemicals have underlined the importance of effective surveillance of hypospadias prevalence in the population. We report here the prevalence of hypospadias from 1980 to 1999 in 20 regions of Europe with EUROCAT (European Surveillance of Congenital Anomalies) population-based congenital anomaly registers, 14 of which implemented a guideline to exclude glanular hypospadias. We also report data from the England and Wales National Congenital Anomaly System (NCAS). Our results do not suggest a continuation of rising trends of hypospadias prevalence in Europe. However, a survey of the registers and a special validation study conducted for the years 1994-1996 in nine EUROCAT registers as well as NCAS identified a clear need for a change in the guidelines for registration of hypospadias. We recommend that all hypospadias be included in surveillance, but that information from surgeons be obtained to verify location of the meatus, and whether surgery was performed, in order to interpret trends. Investing resources in repeated special surveys may be more cost-effective than continuous population surveillance. We conclude that it is doubtful whether we have had the systems in place worldwide for the effective surveillance of hypospadias in relation to exposure to potential endocrine-disrupting chemicals.

Risk of hypospadias in relation to maternal occupational exposure to potential endocrine disrupting chemicals

Background: Reported rises in the prevalence of hypospadias and other abnormalities of the male reproductive system may be a result of exposure to endocrine disrupting chemicals. Aims: To analyse the...