Birth defects surveillance in China.
BACKGROUND
Birth defects are a global public health problem because of their large contribution to infant mortalities and disabilities. It is estimated that 4%-6% of Chinese newborns are affected by birth defects every year. Surveillance is a basic approach to understanding the occurrence and associated factors of birth defects. The Ministry of Health of China initiated a national hospital-based birth defects monitoring system 20 years ago. Nearly every province in this country has established its own surveillance system in the past. The authors reviewed the result of the monitoring system at different administrative levels in China.


METHODS
Available publications on the surveillance of birth defects and data from national and provincial birth defects surveillance systems were reviewed to evaluate the effectiveness of the surveillance systems.


RESULTS
According to the 2009 data, the national hospital-based birth defects surveillance system monitored over 1.3 million births, which accounted for more than 8% of births in China. In addition, 30 provincial hospital-based surveillance programs covered a birth population of more than 3.6 million (22% of births in China). Great achievements have been made in terms of case ascertainment, data quality control, and online reporting. But the surveillance systems in China still have some limitations. A short ascertainment period may miss some internal anomalies, inherited metabolic diseases, and malformed fetus aborted before the 28th gestational week. Discrepancies in antenatal or postnatal diagnosis of birth defects between surveillance institutes may affect the detection rate and introduce biases. Absence of baseline data and lack of integrated database systems limit the application of surveillance data to etiological studies and affect the process of decision-making.


CONCLUSIONS
The surveillance system for birth defects is prerequisite to propose, conduct and assess any interventions for the disease. To meet the need of study and prevention of birth defects, measures should be taken to improve the national and provincial birth defects surveillance systems in China.
National Center for Birth Defects Monitoring, West China Second University Hospital, Sichuan University, Chengdu 610041, China.
Li
L
Dai
Jun
J
Zhu
Juan
J
Liang
Yan-Ping
YP
Wang
He
H
Wang
Meng
M
Mao
D002681:China / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000453:epidemiology*; D003625:Data Collection; D006306:Health Surveys / Q000266:history / Q000706:statistics & numerical data; D049673:History, 20th Century; D006801:Humans; D011159:Population Surveillance; D015995:Prevalence