Time trends in oral clefts in Chinese newborns: data from the Chinese National Birth Defects Monitoring Network.

BACKGROUND Although the prevalence of oral clefts in China is among the highest in countries worldwide, little is known about its descriptive epidemiology. METHODS Data used in this study were collected from 1996 to 2005 using the nationwide hospital-based registry, the Chinese Birth Defects Monitoring Network. A total of 4,891,472 newborns (live or still births with 28 weeks of gestation or more) delivered in member hospitals were assessed for birth defects within 7 days following birth. RESULTS The prevalence of nonsyndromic, syndromic, and overall clefts was 14.23, 2.40, and 16.63 per 10,000, respectively. An upward time trend in the prevalence of nonsyndromic cleft palate and nonsyndromic cleft lip was detected. Cleft lip with or without cleft palate showed a different pattern by gender, urban-rural classification, and geographic location when compared to cleft palate, particularly for nonsyndromic cases. Maternal age was associated with prevalence of all oral clefts. Neonates with oral clefts had increased rates of mortality. CONCLUSIONS The observed complex patterns of prevalence of oral clefts from the Chinese national birth defects registry indicate that oral cleft subtypes by either cleft location or syndromic status should be considered in the development of intervention measures and in future analytical studies.