OBJECTIVETo learn the prevalence of birth defects in Chongqing.

METHODSA total of 6579 children aged 0 - 4 were chosen by multistage cluster sampling method in central economic districts of Chongqing. A total of 32 kinds of birth defects were selected. All the birth defects, except for the visible congenital malformation, must be diagnosed by the hospital in county. And municipal experts would make a consultation for those that couldn't be diagnosed at the level of county. Investigators trained strictly made a body examination and inquired medical history from May to September in 2010.

RESULTSA total of 6541 subjects, aged from 0 to 4, were recruited in the present study, and 216 of them were born with birth defects. The total prevalence was 33.48‰ (95%CI: 29.09‰-37.87‰). There were 25 kinds of birth defects in total, the first five were hernia (20.15‰), congenital heart disease (2.17‰), polydactylism (2.02‰), cryptorchid (1.86‰) and funnel chest (1.86‰). The prevalence among boys was 52.99‰ (178/3359), higher than girls 12.29‰ (38/3092) (χ2=82.42, P<0.05). The prevalence in each group aged 0, 1, 2, 3, 4 were 39.30‰ (36/916), 38.79‰ (41/1057), 36.46‰ (56/1536), 28.38‰ (47/1656), 27.99‰ (36/1286), respectively. There were no statistical differences in each group (χ2=4.83, P=0.31). The prevalence in countryside was 40.17‰ (136/3386), higher than that in town 26.18‰ (80/3065) (χ2=9.83, P<0.05).

CONCLUSIONThe rate of birth defects in Chongqing was moderate, and boys and kids in rural areas had a higher prevalence rate than their counterparts.