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Patterns of Anomalies

A baby may have a single anomaly or a complex pattern of anomalies affecting many different body systems. The pattern of anomalies, together with a thorough knowledge of embryology can in some cases help point to possible causes.

For cases reported to CARIS:

  • 60% of cases have a single anomaly
  • 58% of those affected were male, 40% were female and the remainder were unknown or not recorded, apart from 14 who were described as intersex
  • 11.6% of cases have a chromosomal anomaly

Survival outcome varies with the pattern of anomalies. As expected survival rates are highest for babies with single anomalies. As the number and complexity of anomalies increases, survival reduces.

Poorer survival is associated with increased rates of natural losses but also with termination of pregnancy following antenatal detection of anomalies.


Main anomaly groups

CARIS classifies anomalies by the body system that is mainly affected. Rates for these groups are shown. Cardiovascular anomalies still are the largest group followed by limb defects and musculoskeletal anomalies.


Risk factors

Risk factors for congenital anomaly can be classified in many different ways, for example:

  • Pre-existing parental factors, including maternal age, maternal medical conditions, socio economic status and genetic factors.  This could include consanguinity.
  • Exposures to the foetus during pregnancy, including lifestyle factors, drug exposures, infection and environmental exposures