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Birth Defects

A birth defect is an abnormal development of the foetus resulting in death, malformation, growth retardation, and functional disorders. In the U.S. approximately 150,000 babies are born each year with birth defects, with approximately 3% of all children having a major malformation at birth. Many more show problems of developmental origin with time, e.g., 6-7% by 1 year of age and 12-14% by school age.

Birth defects, including low birth weight babies, are the leading cause of infant mortality. The causes of birth defects have been broken down into the following:

  • About 10% of problems seen at birth can be traced to a specific agent such as an environmental agent, drug , biologic, or nutritional factor, (cf. also teratogens ).
  • About 20% are inherited or are associated with chromosomal changes (cf. also genetic screening ).
  • The remaining 70% or so are of unknown cause, although a 1991 report from the General Accounting Office found that a majority of experts believe that a quarter or more of birth defects will be found to have been environmentally induced.

While some types of birth defects have decreased, mainly through preventive methods, many have increased (for example, several cardiac defects, chromosomal defects such as trisomy 18, and foetal alcohol syndrome ).

The information in this page is presented in summarised form and has been taken from the following source(s):
1. Physicians Committee for Responsible Medicine:

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Contact Last modified: Jun 24 2002