| Background:Heavy metals are important environmental pollutants.Cadmium and chromium have been identified as class I human carcinogens by the International Agency for Research on Cancer(IARC).With rapid socio-economic development,environmental pollution is becoming a critical problem in the pearl river delta region.The data from previous studies showed that the concentrations of cadmium,chromium in air,soil and sediments of Guangzhou and Foshan cities,Guangdong province were much higher than National limits standard.The pregnancy period is a critical important period,on the one hand,various organs of fetus are growing quick to reach maturity,and on another hand,the pregnancy period is sensitive period to have adverse impacts to fetus when the pregnant women were exposed by environmental pollutants although low dose exposure,such as heavy metals.The data from numerous epidemiological studies indicate that neonatal growth could be affected by exposure to cadmium and chromium during pregnancy,but the data are almost from cross-sectional studies.In this study,healthy pregnant women aged 20-45 years from Guangdong maternal and child healthcare hospital at Panyu district,Guangzhou city and Nanhai maternal and child healthcare hospital,Foshan city were recruited and a birth cohort study has been establishing to investigate longitudinal effects on growing and development of fetus?neonatal and infant exposure to cadmium and chromium during pregnancyObjective:The concentrations of urinary cadmium and chromium were analyzed by using ICP-MS method and measurement of fetal biparietal diameter,head circumference,abdominal circumference and femur length at 13th,24th and 32nd week after pregnancy using B-ultrasound and measurement of body length,body weight and head circumference at 0,1,3 and 6 month after birth were collected to investigate longitudinal effects on growing and development of fetus?neonatal and infant during exposure to cadmium and chromium at first trimester and third trimester of pregnancyMethods:377 healthy pregnant women aged 20-45 years who were registered and documented in Guangdong provincial maternal and child healthcare hospital at Panyu district and Nanhai maternal and child healthcare hospital,Foshan city were recruited,and 10 mL of urine samples were collected at at first trimester(<14 weeks)and third trimester(>34 weeks)in pregnancy.The concentrations of urinary cadmiun and cluromium were analyzed by using ICP-MS.Measurement of fetal biparietal diameter,head circumference,abdominal circumference and femur length were collected at 13th,24th and 32nd week after pregnancy by using B-ultrasound.Measurement of body length,weight and head circumference at 0,1,3 and 6 month after birth were collectedData analysis were performed using SPSS 20.0 and Graph Prism 6 software.The percentile method was used to describe the exposure level of cadmium and chromium in different period of pregnancy.Natural logarithm was used as the base to conver normal distribution of the values of urinary cadmium and chromium.The values of urinary cadmium and chromium were divided into three groups including low exposure group(P?25),middle exposure group(P25-P75)and high exposure group(P>75).The longitudinal effects on growth and development index of fetus and neonate was analyzed by linear regression.The longitudinal effects on infant were observed by comparison with WHO standard curve published in 2006Results:1.The median exposure level of urinary cadmium and chromium at first trimester of pregnancy were 1.00?g/g creatinine and 1.15?g/g creatinine respectively.The median exposure levels of urinary cadmium and chromium at third trimester of pregnancy were 0.91 ?g/g creatinine and 1.29 ?g/g creatinine respectively2.A negative correlation between in high exposure level of urinary chromium at first trimester and BPD was observed by comparison with low exposure level of urinary chromium(?=-0.50,95%CI:-0.85,-0.14),and the negative correlation was significant observed in girls after analysis of gender stratification;A negative correlation between high exposure level of urinary chromium and HC at 24th week after pregnancy was observed(?=-0.62,95%CI:-1.15,-0.10),and no significant correlation was observed after gender stratification(P>0.05).No correlation was observed between the level of urinary chromium exposure and growing indicators at 32nd week after pregnancy;and no correlations were observed between the level of urinary cadmium exposure and the growing indicators at 24th and 32nd week after pregnancy.3.The significant differences between the level of urinary cadmium,chromium at first trimester of pregnancy and neonatal head circumference were observed.Negatively correlations between high ?=-0.89,95%CI:-1.44,-0.23)and middle(?=-0.69,95%CI:-1.14,-0.23)exposure levels of urinary cadmium at first trimester of pregnancy and neonatal head circumference were observed respectively by comparison with low exposure level of urinary cadmium;The correlations were significant observed in boys after analysis of gender stratification(P<0.05).Negatively correlations between high level of urinary chromium and neonatal head circumference(?-0.62,95%CI:-1.13,-0.10)and birth weight(?=152.39,95%CI:-294.54,-10.25)were observed,and no significant correlation was observed after the analysis of gender stratified.No significant correlations were observed between the level of urinary cadmium and chromium and growth indicators of neonates4.The significant differences of growing indicators were observed between male and female infant in different age(P<0.05).A negative correlation was observed between level of urinary chromium at first trimester of pregnancy and body length of infant at 3rd month(?=-0.95,95%CI:-1.49,-0.41)after birth.Negatively correlations were observed between level of urinary chromium at first trimester of pregnancy and body weight at 1st month(?=-0.1 3,95%CI:-0.25,-0.01)and 3rd month(?=-0.18,95%CI:-0.36,-0.004)after birth.The growth of infant is fast in first 3 months and the growth trajectory of infant were similar with WHO standard curve published in 2006Conclusion:In this study,the concentrations of urinary cadmium and chromium in subjects are higher than National limit standard.The growth of fetus and neonatal were affected by exposure of urinary cadmium and chromium exposed at first trimester of pregnancy.No significant differences were observed between the growth of fetus and neonate and level of urinary cadmium and chromium exposed at third trimester of pregnancy.Growth trajectory of infant aged 0-6 months in this study are similar with WHO standard curve published in 2006. |
PDF Full Text Request