[Epidemiology of neural tube defects in China].

During a period of 12 months (Oct. 1986 to Sep. 1987), 1,243,284 live and still births from 28 weeks of gestation to a period within 7 days after delivery were monitored in 945 hospitals of 29 provinces, cities and autonomous regions of China. A total of 3,404 cases of neural tube defects were recorded, among which there were 1,891 cases of anencephaly (55.6%), 1,050 cases of spina bifida (30.9%) and 463 cases of encephalocele (13.6%). The incidence of neural tube defects in China varied from 6.6 to 105.5 with a mean of 27.4 per 10,000. A female preponderance (35.7 per 10,000) over the male (19.2 per 10,000) was noted (P less than 0.01). The incidence of neural tube defects in the rural area (51.7 per 10,000) is higher than that in the urban area (15.5 per 10,000), (P less than 0.01).