[Dynamic monitoring of neural tube defects in China during 1996 to 2000]

The database from Chinese Birth Defects Monitoring Network was used to describe the epidemiological features and secular trends of neural tube defects (NTDs) prevalence during Jan. 1996 to Dec. 2000, including anencephaly, spina bifida and encephalocele.

Data were collected with hospital-based cluster sampling method. During the period, all live or still births with 28 weeks or more of gestation were assessed within seven days after delivery.

There were 2 873 case with NTDs identified from 2 281 616 births, with an overall prevalence rate of 12.95 per 10,000 births. And, the prevalence rates of anencephaly, spina bifida and encephalocele were 5.02 per 10,000, 6.30 per 10,000 and 1.64 per 10,000, respectively. Significant falls in overall prevalence rates of NTDs and of anencephaly were observed. The prevalence rates of NTDs were 9.75 per 10,000 and 15.96 per 10,000 in male and female births, respectively, 7.76 per 10,000 and 25.20 per 10,000 in the urban and rural areas, respectively, and 19.90 per 10,000 and 5.81 per 10,000 in north and south China, respectively. The prevalence was higher in the groups with maternal age of less than 20 years and more than 30 years than in those other maternal ages. Preterm babies and babies with low birth weight accounted for 50.9% and 50.6% of perinatal babies with NTDs, respectively, with a perinatal mortality of 77.8%.

In China, the occurrence of NTDs was higher in female births than in male births, higher in the rural than in the urban, and higher in the north than in the south. Annual prevalence rate of NTDs in China presented a declining trend, but still higher than that in the other countries at the same time period. Babies with NTDs were in poor birth quality, higher perinatal mortality and poor prognosis. Effective preventive measures and prenatal diagnosis should be strengthened to reduce the occurrences of neural tube defects.