NCARDRS Congenital Anomaly Official Statistics Report, 2020

Birth prevalence describes the occurrence of congenital anomalies and is used as a measure of the burden of disease.

Total prevalence and live birth prevalence are the two most commonly used measures. Total prevalence is defined as the total number of babies with a congenital anomaly occurring in all pregnancy outcomes (live births, stillbirths, late miscarriages between 20-23 complete weeks and terminations at any gestation) per 10,000 live births and stillbirths (total births). 

Live birth prevalence is the total number of congenital anomalies occurring in live births per 10,000 live births.

 Data table 1 shows that a total of 13,065 babies with one or more congenital anomalies were notified to NCARDRS in 2020 out of 589,454 total births (live births and stillbirths) in England. This gives an overall birth prevalence of congenital anomalies of 221.7 per 10,000 total births (95% confidence intervals (CI): 217.9 - 225.5). This reflects one baby diagnosed with a congenital anomaly for every 45 births (live births and stillbirths).

While there is regional variation in the overall prevalence of congenital anomalies, Figure 1b and Data table 2b show that prevalence across NCARDRS regions was more consistent when regional prevalence is restricted to babies with one of the conditions audited by the NHS Fetal Anomaly Screening Programme (FASP). NCARDRS has worked with the FASP programme since 2015 in a partnership auditing detection rates for three trisomy conditions, four severe cardiac conditions, two abdominal wall conditions, along with spina bifida, anencephaly, lethal skeletal dysplasia, cleft lip +/- palate, bilateral renal agenesis and congenital diaphragmatic hernia. As part of this work, these conditions are subject to more intensive reporting, resulting in higher data quality and ascertainment.

Figure 1b: The number of babies with at least one congenital anomaly that is a FASP condition per 10,000 total births (prevalence) and 95% confidence intervals, for NCARDRS regions compared to England, 2020

Geographical variation in congenital anomaly prevalence is most likely due to differences in case ascertainment resulting from different data sources, access to remote data systems and the regional variation in the length of time registration has been established. However, there are other reasons which could influence the results presented such as disease clustering, exposure to teratogens, demographic variation including maternal age, deprivation profiles between regions and the composition of the local population.

As NCARDRS accumulates more data at a national level over time, and registration in newer regions matures, greater insights will be gained into underlying population characteristics contributing to regional variation, as well as the ability to analyse associations with lifestyle and environmental factors which may potentially be modifiable.