| BackgroudHuaihe River Basin water pollution began in the 1970s. Historical information displays, the first water pollution happened in 1975. Since entering 1980s, along with economic development and acceleration urvanization, the Huaihe River Basin water pollution has become more and more serious. As one of a branch of the Huaihe River, Kuihe River has been polluted. Some researchers had evaluated water quality of Kuihe river and found that the river was polluted seriously, the quality level of river water was V level. Chemicals in polluted river had mutagencity and caused gene mutation and chromosoe structure variation, affected the pregnancy process, and led to spontaneous abortion, stillbirth and other adverse pregnancy outcomes. Adverse pregnancy outcomes such as spontaneous abortion, which can be treated as recent indicators of the impact of water pollution on health outcomes, maybe was a sensitive indicator of the impact of water pollution on women’s health. It is so important to investigate and analyze the status of spontaneous abortion of women along the Kuihe River and its influencing factors, especially the relationship between the water pollution and spontaneous abortion, for learning the impact of the Kuihe River water pollution on women’s health, prevention of spontaneous abortion and improvement of women’s reproductive health. Considering that Huaihe River water pollution was starting in the 1970s, the water pollution was serious before 2005, and the proportion of women who had children in 20-29 years old was 93.26%, this study selected the female people who was born on 1955 to 1975 as the research object. This study analyzed the status and risk factors of women and explored the relationship between the spontaneous abortion of women and the distance from Kuihe River.Objective1. To describe and analyze the status of spontaneous abortion of women along Kuihe River and its risk factors.2. To explore the relationship between spontaneous abortion of women and the distance from Kuihe River.Methods1. Survey methods(1) The study was launched in Yongqiao district, Anhui province in 2012,2013 and 2015. Cluster random sampling was applied to select 75 villages from 9 towns along Kuihe river. A qualified person was selected to be investigated by KISH table method from each family of each village which has been selected. All individuals were registered to live there,aged between 40 to 80, lived in study area more than six months in the past 12 months and completed the informed consent procedure. Exclusion criteria: The people who can not cooperate with the research because of the limited behavioral cognitive ability and pregnant women were not included in this study. We selected women who were born on 1955 to 1975 and settled down in native village after marriage from those individuals who were selected by the criteria as research objects.(2) We collected data through household interviews by trained interviewers, using unified questionnaire which including the times of pregnancy, the times of delivery, spontaneous abortion, induced abortion, demography Characters, contacting risk factors before pregnancy and so on. To locate village which was selected by trained interviewers using GPS locator, measured the longitude and latitude of the village at the village committee, branch or village health room door and recorded them.2. Statistic methodsEpiData was used to establish a database to with double entry, using SAS 9.3 statistical software for data analysis.(1) Described the distribution of the ratio between spontaneous abortion and pregnancies, the spontaneous abortion rate (SAR) and the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey in social-demographic characteristics. The difference of rate was evaluated by Chi-square test.Significance was set at P< 0.05.(2) The univariate analyses were used to analyze the risk factors of spontaneous abortion of women along Kuihe River. Significance was set at P< 0.05.(3) The study area was divided into different groups according the position relationship between village and 5 km buffer of the river. The ecological comparison study was used to analyze the relationship between spontaneous abortion of women and the distance from Kuihe River.(4) To analyze the relationship between spontaneous abortion of women and the distance from Kuihe River after accounting for other risk factors by taking the multivariate stepwise regression analysis with having spontaneous abortion or not as the dependent variable while statistically significant variables in single factor analysis and the distance from Kuihe River as the independent variable.Results1. The prevalence of spontaneous abortion of women along Kuihe River(1) There were 4491 women under study with a total number of 12536 pregnancies including 10887 deliveries,500 spontaneous abortive episodes,62 fetal deaths and 1079 induced abortion. There were 402 women had experienced spontaneous abortion and 60 women had experienced fetal death.(2) The ratio between spontaneous abortion and pregnancies was 3.99%, the SAR was 4.36% and the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey was 8.95%. The fetal death rate was 0.54% and the ratio between the number of women who had experienced fetal death and total number of women under survey was 1.34%.(3) The ratio between spontaneous abortion and pregnancies and the SAR increased over time and the Trend/test was statistically significant(Z=5.474, P＜0.001; Z=5.894, P＜0.001)2. The univariate analysis of the risk factors of spontaneous abortion of women along Kuihe River.(1) First marriage age:Of all women under survey, the number of women whose first marriage age was from 20 to 24 was higest, which accounted for 64.87%, while the women whose first marriage age was more than 35 accounted for 1.16%. Since the age of 20, with increasing the year of first marriage age, the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey has increased, and the Trend χ2 test was statistically significant (Z=3.446, P<0.001).Compared with the women whose first marriage age was 20-24, the women whose first marriage age was<20,25-29,30-34 and ≥35 had higher risk for spontaneous abortion, the OR were 1.184 (95%CI:0.898-1.560),1.190 (95%CI: 0.888-1.593),2.127 (95%CI:1.158-3.907),2.714 (95%CI:1.343-5.487),respectively.(2) Smoking before pregnancy:There were 36 women had smoked before pregnancy, and the rate of smoking before pregnancy was 0.80%. There was no sitatistically significant difference among the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey between women who had smoked before pregnancy and women who had not (χ2=1.057, P=0.304).(3) Passive smoking before pregnancy:There were 676 women had exposured secondhand smoke before pregnancy, and the rate of passive smoking before pregnancy was 17.92%. The ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey of passive smoking group was higher than that of no passive smoking group, and the difference was statistically significant(χ2=7.392,P=0.007), the OR was 1.439 (95%CI:1.107-1.871)(4) Drinking before pregnancy:There were 634 women had drinked before pregnancy, and the rate of drinking before pregnancy was 14.15%. The ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey of drinking group and no drinking group was 10.73% and 8.66% respectively, and there was no sitatistically significant difference between two groups(χ2=2.839, P=0.092).(5) Contacting pesticide before pregnancy:There were 1974 women had contacted pesticide before pregnancy, and the rate of contacting pesticide before pregnancy was 43.96%. The ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey of contacting pesticide group was higher than that of no contacting pesticide group, and the difference was statistically significant(χ2=5.978,P=0.015), the OR was 1.291 (95%CI:1.052-1.585)(6) Contacting benzene before pregnancy:There were 4 women had contacted benzene before pregnancy, and the rate of contacting benzene before pregnancy was 0.09%. There was no statistically significant difference in the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey between two groups(χ2=1.122, P=0.290).(7) The times of pregnancy:The difference between the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey of women among different pregnancies groups was significant (χ2=305.353, P＜0.001). The ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey of women whose pregnancies was more than 3 was higher than that whose pregnancies was less than 3,the OR was 6.810 (95% CI:5.491-8.445)3. The relationship between the spontaneous abortion of women along Kuihe River and the distance from Kuihe River(1) The buffer analysis result indicated that there were 23 villages inside the 5km buffer of Kuihe River(study area),52 villages out of the 5km buffer of Kuihe River(control area). The ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey of women in study area was higher than that in control group, and the difference was statistically significant(χ2=6.811, P=0.009), the OR was 1.324 (95%CI:1.072-1.635)(2) The distribution of prevalence of the year of birth was balanced between study area and control area, as were the other factors related with spontaneous abortion of women such as first marriage age, pregnancies, passive smoking before pregnancy, drinking before pregnancy and contacting pesticides before pregnancy.(3) Multivariate Logistic regression analysis showed that the distance from Kuihe River was the influence factor of spontaneous abortion of women after controlling other factors. The risk of spontaneous abortion of women whose distance from Kuihe River was no more than 5km was higher than that of women whose distance from Kuihe River was more than 5km, the OR was 1.433(95%C7:1.138-1.803).4. The further study of relationship between water pollution and spontaneous abortion of women along Kuihe River(1) The buffer analysis result indicated that there were 2 villages in A area(inside 5km buffer of Kuihe River and Xinsuihe River),24 villages in B area(inside 5km buffer of Kuihe River or Xinsuihe River),49 villages in C area(not inside of 5km buffer of Kuihe River or Xinsuihe River).The trend chi-square test was used to analyze the distribution of the ratio between spontaneous abortion and pregnancies, the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey in A area, B area and C area were 15.61%,9.84% and 8.06% respectively. The difference was statistically significant(Z=-3.558, P<0.001). The risk of spontaneous abortion of women in A area was higher than that of in B area and C area, the OR were 1.695 (95%CI: 1.171-2.571) and 2.110 (95%CI:1.412-3.151) respectively.(2) The distribution of risk factors of spontaneous abortion in A area, B area and C areaThe difference of prevalence rate of women’s year of birth among A area、B area and C area was not statistically significant(χ2=2.993, P=0.810), as was first marriage age(/=9.021, P=0.341), drinking before pregnancy(χ2= 1.910, P-0.385), contacting pesticide before pregnancy(χ2=2.276, P=0.320) and the times of pregnancy0(χ2=2.300, P=0.681). The difference of prevalence rate of passive smoking before pregnancy among A area> B area and C area was statistically significant(χ2=7.476, P=0.024). The prevalence rate of passive smoking before pregnancy was highest in A area.(3) Stratified analysis:The relationship between river pollution and spontaneous abortion of women was further stratified by passive smoking before pregnancy. For women who was passive smoking before pregnancy, the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey were 20.59%,11.69% and 11.62% respectively, and the difference was not statistically significant(Z=-0.969,P=0.166); For women who was not passive smoking before pregnancy, the ratio between the number of women who had experienced spontaneous abortion and the total number of women under survey were 17.32%,9.98% and 7.69% respectively, and the difference was statistically significant(Z=-3.678, P< 0.001).(4) Multivariate Logistic regression analysis showed that the distance from polluted river was the influence factor of spontaneous abortion of women after controlling other factors. The risk of spontaneous abortion of women in A area was higher than that of in B area and C area, the OR were 1.809 (95%CI:1.145-2.857) and 2.314 (95%CI:1.489-3.594) respectively. The risk of spontaneous abortion of women in B area was higher than that of in C area, the OR were 1.279 (95%CI:1.001-1.635)Conclusion1. The spontaneous abortion rate of women along the Kuihe River was high. The spontaneous abortion rate increased over time.2. Women whose distance from Kuihe River was close had a higher risk of spontaneous abortion. The spontaneous abortion of women along the Kuihe River maybe was related with water pollution of Kuihe River. |
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