[Evaluation on birth defects surveillance system in four counties of Shanxi province, China]

To evaluate the reliability of the birth defects surveillance system in four counties with high prevalence of birth defects (Pingding, Xiyang, Taigu and Zezhou counties) in Shanxi province, China.

One township was selected from each county as study site. The health workers chosen from township or village level were trained to visit families on the outcomes of each pregnancy who gave birth during year 2003 in the study site. The number of births and cases collected in the study were compared with that from the surveillance system. The number of births reported by surveillance system in four counties was also compared with the data from the local government. The criteria of evaluation were: 1) number of the missing report of births should < or = 5%, 2) the number of missing report on major external birth defects cases should < or = 10%. Researchers from the Peking University were responsible for examining the quality of surveillance in some terminal units of surveillance system.

The numbers of births reported in the study and from the surveillance system for four-township were 1043 and 997, respectively. 46 births were missing and the rate of misreporting for births was 4.4%. The numbers of birth defects cases reported in the study and from the surveillance system were 30 and 29, respectively. 1 case of birth defect as missed, and rate of misreporting for birth defects cases was 3.3%. The total number of births reported from surveillance was similar to that in the study in four counties, with a difference of 1.2%. Birth registry data was rather readable and special health workers responsible for surveillance work were present in all the terminal units of the surveillance system.

The misreporting of births and cases existed in the birth defects surveillance system of the four counties in Shanxi province, but were lower than the allowable criteria. The surveillance units had better registration, reporting and administration of births and birth defect cases. Hence, the quality of the data from the surveillance system in these four counties was reliable.