Geographic and urban-rural disparities in the total prevalence of neural tube defects and their subtypes during 2006-2008 in China: a study using the hospital-based birth defects surveillance system

Background: Previous reports on the prevalence of neural tube defects (NTDs) in China did not include cases of NTDs that were less than 28 weeks of gestational age (GA) and hence did not accurately reflect the total prevalence of NTDs or the geographic and urban-rural disparities in their prevalence. This article includes cases of NTDs that were less than 28 weeks of GA. Methods: Data used in this study were collected from 2006 to 2008 using a nationwide hospital-based registry, the Chinese Birth Defects Monitoring Network. The total prevalence ratio (PR) of NTDs and their subtypes, the ratios of PR (PRR), and 95% confidence intervals (CI) were used to analyse geographic disparities at both the regional (north, south) and provincial levels and to analyse disparities between rural and urban areas. Results: Overall, the total PR of NTDs was 14.0 per 10,000 births. The PRR of NTDs of rural women between the north and south region was 2.26 (95% CI: 2.04-2.52), which was much higher than that of urban women (PRR: 1.56, 95% CI: 1.41-1.72). The three subtypes of NTDs had different geographic distribution at the level of province. The urban-rural PRR of NTDs was 2.14 (95% CI: 1.94-2.34) in the north but only 1.47 (95% CI: 1.31-1.66) in the south. Conclusions: There is a high total prevalence of NTDs, which remains one of the major public health concerns in China. Eliminating the geographic and urban-rural disparities in the disease burden is a priority for future intervention.