Study on the descriptive epidemiology of pregnancy-induced hypertension from 1995 - 2000 in Jiaxing of Zhejiang province, China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To describe the epidemiological characters of pregnancy-induced hypertension (PIH) in Jiaxing areas of Zhejiang province of China between 1995 and 2000.</p><p><b>METHODS</b>We analyzed the perinatal health surveillance data that was collected as part of the Sino-American cooperative project on neural tube defects prevention established in 1992. The study population consisted of 136 070 pregnant women with at least 20 weeks of gestational age. National diagnostic criteria were used to identify the cases which were divided into three subgroups: mild, moderate and severe.</p><p><b>RESULTS</b>15 127 cases were identified and the overall incidence rate of PIH was 11.1% (95% CI : 11.0% - 11.3%). Among all the cases, mild, moderate and severe PIH were accounted for 71.4%, 22.3% and 6.3%, respectively. The proportions of PIH cases that occurred in the second trimester, third trimester and during delivery appeared to be 4.2%, 34.4% and 61.4%, respectively. There was a significant fall in the trend of PIH occurrence every year, which dropped from 10.7% in 1995 to 8.6% in 2000 by 19.6%. More risk of PIH seemed to be related to those mothers living in the urban areas with age under 20 or above 35, being peasants and having little educational, having had multiple gestations, conceiving in spring/summer or delivering in winter or spring etc. Compared with the results of national survey in 1988, the incidence rate of PIH was higher by 18.1%, while the proportion of severe PIH was much lower by 68.8%. Although the incidence rates of PIH in urban and rural areas were somehow similar, the proportion of severe PIH in rural areas was much higher than that in urban areas.</p><p><b>CONCLUSION</b>Overall incidence rate and distribution of PIH were reported. Compared with the results in 1988, incidence rate of PIH was much higher, particularly for mild cases.</p>

Premature, low birth weight, small for gestational age and childhood cerebral palsy / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the relationship between perinatal risk factors such as premature, low birth weight, small for gestational age and childhood cerebral palsy (CP).</p><p><b>METHODS</b>A cross sectional survey was carried out among 305,263 children aged 1 - 6 years old in seven cities of Jiangsu Province, China from May to July 1997. The perinatal risk factors were analysed.</p><p><b>RESULTS</b>Four hundred and eighty-four cases of CP were found among this population. The prevalence of CP for children aged 1 - 6 years old was 1.59 per thousand. The prevalence of CP were strongly correlated to prematurity (RR = 25.16), low birth weight (RR = 19.63), and also highly correlated to small for gestational age (RR = 4.34). For smaller groups divided by small for gestational age (SGA), appropriate for gestational age (AGA), large for gestational age (LGA) and then by gestational age, prematurity was found to be at high risk in SGA (RR = 9.29), AGA (RR = 28.34) and LGA (RR = 21.41) groups. For groups divided by gestational age and then by SGA, AGA and LGA, SGA was found to have significantly high risk in premature (RR = 1.45), mature (RR = 4.41) and postmature (RR = 3.19) groups. Nine groups were divided by the gestational age along with SGA, AGA and LGA, rates of CP were found to be significantly higher in most groups than in the term AGA group. Compared with the rate of CP in the term AGA group, the RR were calculated and showed as followings (from higher to lower), premature SGA (RR = 40.99), premature AGA (RR = 28.34), premature LGA (RR = 21.08), postmature SGA (RR = 8.39), mature SGA (RR = 4.41) and postmature AGA (RR = 2.63).</p><p><b>CONCLUSION</b>Prematurity and small for gestational age are both independent risk factors for cerebral palsy. Postmaturity and large for gestational age are not risk factors.</p>

The epidemiology of neural tube defects in high-prevalence and low-prevalence areas of China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To describe the epidemiology of neural tube defects (NTDs) in high- and low-prevalence areas of China.</p><p><b>METHODS</b>Birth defects surveillance data, collected from 1992 through 1994 was analyzed. These data were collected as part of the Sino-American cooperative project on NTDs prevention. We classified NTDs as anencephaly, encephalocele, high-level and low-level spina bifida (SB) according to location of the lesion (high vs low) and whether the defect was isolated or occurred in association with other birth defects. Rates were compared in the high-prevalence (North) region and the low-prevalence (South) region, after adjusted for classification, urban and rural, season and sex, and calculated the adjusted rate of NTDs.</p><p><b>RESULTS</b>Among seven hundred and eighty-four NTDs cases in 326 874 recorded births (include in livebirth, stillbirth and fetal death with a gestational age of at least 20 weeks), the overall NTDs prevalence in the North was 5.57/1,000 births, and in the South was 0.88/1 000. There were also significant differences in the prevalence of anencephaly, encephalocele, high-level and low-level SB between North (0.97, 0.49, 2.75 and 1.11/1,000 birth) and South (0.36, 0.15, 0.21 and 0.14/1,000 birth) (P < 0.01), with adjusted prevalences in the North 3 - 7 times higher than those in the South. There were significant difference between urban (2.04) and rural areas (6.57/1,000 birth) in the North (P < 0.01), urban (0.52) and rural areas (0.95/1,000 birth) in the South (P < 0.05). Adjusted prevalence rates in the rural were 3 - 4 times higher than those of urban in the North and 1.6 - 1.9 times higher than in the South; The seasonal rate of high-level SB increased between September and November in the North (3.44/1,000 birth), while the seasonal rate of anencephaly decreased between September and November (0.18/1,000 birth) in the South. However there were no seasonal changes in other classified NTDs both in the South and North.</p><p><b>CONCLUSIONS</b>The birth prevalence of NTDs in the North of China was the highest in the world. There were significant differences between the North and the South, urban and rural. There was seasonal change in high-level SB in the North, which was in accordance to the phenotype of NTDs. It was suggested that there might exist etiological heterogeneity among anecephalus, low- and high-level SB.</p>

Sex distribution of neural tube defects and their birth outcome in high- and low-prevalence areas of China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To describe and analyze epidemiological characteristics of babies with neural tube defects (NTD) by sex and birth outcome in a high-prevalence and a low-prevalence areas of China.</p><p><b>METHODS</b>Birth defects surveillance data collected from 1992 through 1994, as a part of the Sino-American cooperative project on NTD prevention, were used to classify NTD as four categories, i.e., anencephaly, encephalocele, high-level and low-level spina bifida according to the sites of lesion (high vs. low level lesion were cervicothoracic and lumbosacral, respectively). Each category was sub-classified, according to single or compound defect, as isolated external defects (including those with NTD only) or multiple external defects (including those with NTD and another major external birth defects that is not the sequence of a defect such as cleft lip with or without cleft palate). The rates of anencephalus, encephalocele, high- and low-level spina bifida (SB) in males and females and their sex ratios were calculated, adjusted for urban and rural areas, season, category and birth outcome by sex and sites of lesions (high vs. low).</p><p><b>RESULTS</b>Totally, 784 NTD cases were identified from 326 874 recorded births (including live births, stillbirths and fetal deaths with a gestation age of at least 20 weeks). The prevalence rates of anencephalus (1.30 per 1 000 female births) and high-level SB (3.99) in females were higher than those (0.66 and 1.66 per 1 000 male births) in males in the high-prevalence northern regions; with adjusted prevalence rates of females 1.8 - 2.1 times greater than those of males. In the low-prevalence southern regions, the prevalence of high- (0.32 per 1 000 female births) and low-level SB (0.21) in female were higher than those in males, with high- and low-level SB rate of 0.10 and 0.09 per 1 000 male births), with adjusted rates for females of 1.3 - 1.6 times higher than in males. Isolated NTD accounted for more than 80% of all NTD cases, and the prevalence of isolated NTD in females (2.57) was higher than that in males (1.40).</p><p><b>CONCLUSIONS</b>The sex differences in NTD existed between north and south, in accordance with the phenotype of NTD. It suggested that proportion of high level SB and anencephalus in females could increase as the prevalence of NTD going up, anencephaly, high- and low-level SB had the different genetic and environmental background.</p>