title: [A population-based surveillance system on birth defects and its application].
abstract: OBJECTIVE
  To describe a unique surveillance system on birth defects in the People's Republic of China.
  
  
  METHODS
  The system was instituted in 1992 as a component for the evaluation on the effectiveness of a community intervention program using periconceptional folic acid supplementation to prevent neural tube defects and currently carries out surveys on a birth cohort of approximately 150 000 infants per year. Information was collected in the form of detailed written descriptions by local health care providers and photographs of affected infants. The system allowed for detection of birth defects at the local level with later definitive classification and coding; however, information was limited to those structural anomalies which were visible on physical examination.
  
  
  RESULTS
  This surveillance system on birth defects provides an extensive database of infants with major and minor external structural anomalies. From 1993 to 1996, more than one million births were monitored, with more than 10 000 birth defects and 30 000 photos submitted. Among them 5 000 were identified with major birth defects. Neural tube defects, oral clefts and extremity abnormalities were the first few defects with most cases. Data were used in birth defect surveillance reports and scientific papers.
  
  
  CONCLUSIONS
  This system can be utilized for studies on etiology, descriptive epidemiology, and identification of unusual trends which is unique with multiple advantages in the People's Republic of China.
authors.affiliation: Department of Pediatrics, The Third Hospital, Peking University, Beijing 100083, China.
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Hong
authors.forename: T
authors.initials: T
authors.lastname: Wang
mesh_terms: D000013:Congenital Abnormalities / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy