[Prevalence analysis on congenital hydrocephalus in Chinese perinatal from 1996 to 2004]

To study the epidemiological characteristics of congenital hydrocephalus in Chinese perinatal.

From 1996 to 2004, data gained from Chinese Birth Defects Monitoring Network were used to depict the epidemiology of congenital hydrocephalus in China. All perinatal born in hospitals had an access within 7 days after delivery. The affected cases were divided into two groups-isolated and syndromic hydrocephalus. And prevalence rates were calculated by year, by sex, by birth area (urban versus rural), by maternal age group and by geographic area (north versus south). Of the affected, fetal age at birth, birth weight, perinatal outcome and prenatal diagnosis were analysed.

All 3012 perinatal with congenital hydrocephalus were identified among 4,282,536 births, then an overall prevalence rate was 7.03/10,000, rates of isolated and syndromic hydrocephalus were 5.67/10,000 and 1.36/10,000 respectively. Furthermore, the annual prevalence rates of hydrocephalus presented an increasing trend during that period. The rates in male and female births, in urban and rural area, were 7.09/10,000 and 6.76/10,000, 5.49/10,000 and 10.10/10,000 respectively. There were significant differences among maternal-age-specific prevalence rates, the highest (11.42/10,000) was in an age < 20 years group. For total and isolated hydrocephalus, higher rates were found in north part of China. On the contrary, a higher rate of syndromic hydrocephalus was observed in south part of China. Among the infants with hydrocephalus, the ratio of preterm delivery and of low birth weight were 57.97% and 50.92% respectively. The ratio of congenital hydrocephalus diagnosed antenatally, which could be an indicator representing the capability of detecting the malformation both prenatally and postnatally, showed an upward trend similar to the prevalence rates. The perinatal fatality rates of the total, isolated and syndromic hydrocephalus were 87.75%, 88.66% and 83.91% correspondingly.

Based on comparison between prevalence rates in China and those reported in foreign countries, our country might be listed into a higher epidemic region of the congenital hydrocephalus. Significant differences were identified between rural and urban areas, between north and south parts of China. The improvement ability in prenatal and postnatal diagnosis should be partly accounted for the increasing prevalence rates of hydrocephalus in Chinese perinatal. The poor birth quality of the affected predicts poor prognosis.