[Reliability of birth certificates as a source of information on congenital defects in the City of São Carlos, São Paulo, Brazil].

The reliability of the information on congenital defects listed in birth certificates of the Live Birth Information System (SINASC) in the City of São Carlos, São Paulo, Brazil, was evaluated. A descriptive study that reviewed all 15,249 birth certificates from 2003 to 2007 compared the data with information from medical records and death certificates. Errors in accuracy and precision, mainly related to the description of the anomaly when it was transcribed from medical records to the birth certificates, in addition to coding and the input to SINASC, diminished the reliability of the birth certificates as a source of information on congenital defects. The results suggested that the involvement of the Municipal Health Department is essential to improve SINASC, because this is the location of the coding and input system, and training of the professionals who fill out the birth certificates. With guidance on the importance and function of the birth certificates, SINASC can become an excellent monitoring and surveillance system for congenital defects.