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Objective We aimed to assess the association between urinary bisphenol A(BPA)concentrations and gestational age in pregnant women. Methods A total of 248 pregnant women were recruited from a maternal and child care hospital in Shanghai. A questionnaire survey was completed to collect socio-demographic information and spot urine samples were collected during pregnancy. Gas chromatography-tandem mass spectrometry(GC-MS/MS)was used to measure BPA concentrations in urine samples. Linear relationship between urinary BPA level and gestational age was assessed by using generalized additive models. Multivariate regression model was used to evaluate associations of prenatal BPA exposure with gestational age. Results BPA was detected in all the urine samples. Median value and geometric mean of urinary BPA levels were 0.85 μg/L and 1.21 μg/L, respectively. Linear relationship between urinary BPA concentration and gestational weeks was confirmed(non-linear P > 0.05). Positive association between urinary BPA level and gestational age was indicated(regression coefficient, β = 0.19;95%CI:0.04-0.35;P = 0.016). However, it was only observed in girls, stratified by sex of newborns(β = 0.18;95%CI:0.03-0.34;P = 0.020). After stratification by trimester, no significant association was found in the second or the third trimesters. Conclusion Pregnant women are extensively exposed to BPA. Urinary BPA exposure during pregnancy may extend gestational age, especially in girls.
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<p><b>OBJECTIVE</b>To observe the exposure levels of extremely low frequency electromagnetic fields in workplaces and to analyze the effects of extremely low frequency electromagnetic radiation on cardiovascular system of occupationally exposed people.</p><p><b>METHOD</b>Intensity of electromagnetic fields in two workplaces (control and exposure groups) was detected with EFA-300 frequency electromagnetic field strength tester, and intensity of the noise was detected with AWA5610D integral sound level. The information of health physical indicators of 188 controls and 642 occupationally exposed workers was collected. Data were analyzed by SPSS17.0 statistic software.</p><p><b>RESULTS</b>The intensity of electric fields and the magnetic fields in exposure groups was significantly higher than that in control group (P < 0.05), but there was no significant difference of noise between two workplaces (P > 0.05). The results of physical examination showed that the abnormal rates of HCY, ALT, AST, GGT, ECG in the exposure group were significantly higher than those in control group (P < 0.05). There were no differences of sex, age, height, weight between two groups (P > 0.05).</p><p><b>CONCLUSION</b>Exposure to extremely low frequency electromagnetic radiation may have some effects on the cardiovascular system of workers.</p>