| Objectives1.To explore the effects of maternal prenatal exposure to heavy metal nickel(Ni),copper(Cu)and arsenic(As)on fetal and neonatal growth and development;2.To discuss the barrier effect of placenta on Ni,Cu and As.Methods36 pregnant women in nickel-contaminated areas and 53 control areas were recruited through questionnaires,maternal venous blood and fetal cord blood were collected during the second trimester,third trimester and delivery.The concentration of Ni,Cu and As were determined with the inductively coupled plasma mass spectrometry(ICP-MS).The differences of three heavy metal concentrations in blood samples at different times and the barrier effects of placenta on three metals were analyzed.B-scan ultrasonography was used to detect fetal growth while blood samples were taken every time,including biparietal diameter,femur length,and fetal heart rate.Birth weight,length and head circumference of neonatal were measured at birth.Differences of growth and development indicators of fetal and neonatal at each stage in the two regions and the relationship between the three heavy metals and growth and development indicators of fetal and neonatal were analyzed.Results1.General conditions of pregnant women in two regions:(1)There were no statistical differences in the age,nationality,pre-pregnancy BMI,location of residence,education,occupation and family annual income of pregnant women between the two regions(P>0.05),but there was a significant difference in the years of living(P<0.05);(2)There were no statistical differences about the home decoration in recent one year,distance from the house to the road,families smoking,coworkers smoking,exposure to pesticide during pregnancy,exposure to radiation,formula milk powder(P>0.05),but there was a significant difference in factories near to whose house between the two regions(P<0.05);(3)There were no significant differences in gestational weeks,the ways of delivery and degree of pregnancy response between the two regions(P>0.05).2.The concentrations of Ni and As in maternal blood of contaminated areas in the second trimester were significantly higher than that in the control area(P<0.05),the concentrations of Cu was not statistically different(P>0.05);There were no correlations among Ni,Cu and As in maternal blood(P>0.05);The fetal biparietal diameter and femur length in the contaminated areas were significantly lower than those in the control area(P<0.05,P<0.01),and there was no significant difference in fetal heart rate(P>0.05);As in maternal blood is negatively correlated with biparietal diameter and femur length(r_s=-0.248,P<0.05;r_s=-0.342,P<0.01).3.The concentration of As in maternal blood in contaminated areas in the third trimester was significantly higher than that in the control area(P<0.01),the concentrations of Ni and Cu were not statistically different(P>0.05);There were no correlations among Ni,Cu and As in maternal blood(P>0.05);Fetal femur length was significantly lower in the contaminated area than in the control area(P<0.01),biparietal diameter and fetal heart rate were not statistically differences(P>0.05);Ni,Cu and As are not associated with fetal biparietal diameter,femur length and fetal heart rate(P>0.05).4.The concentration of Cu in maternal blood in contaminated areas at the time of delivery was significantly lower than that in the control area(P<0.05),the concentration of As in maternal blood in contaminated areas at the time of delivery was significantly higher than that in the control area(P<0.01),the concentrations of Ni was not statistically different(P>0.05);There were no correlations among Ni,Cu and As in maternal blood(P>0.05);The length and head circumference of newborns in contaminated areas were significantly lower than those in the control areas(P<0.05,P<0.01),there were no statistical differences in gender,gestational age,and body weight(P>0.05);The concentrations of maternal blood Ni,Cu and As are not related to gestational age,newborn length,weight,and head circumference(P>0.05).5.The concentration of As in cord blood was significantly higher in the contaminated area than in the control area(P<0.01),the concentrations of Ni and Cu were not statistically different(P>0.05);There were no correlations among Ni,Cu and As in cord blood(P>0.05);The concentration of Ni and Cu in cord blood were not related to neonatal gestational age,gender,length,weight and head circumference(P>0.05);The concentration of As in cord blood were not related to neonatal gestational age,gender,length,weight(P>0.05),but As is negatively correlated with head circumference(r_s=-0.245,P<0.05).6.The ratio of cord blood to maternal blood Ni(1.09)was lower in the contaminated area than in the control area(1.30),the ratio of Cu concentration(0.38)is similar to the control area(0.39),the ratio of As concentration(0.88)is similar to the control area(0.83),there were no statistically differences(P>0.05);Combining data from the two regions,the ratio of cord blood to maternal blood Ni concentration is 1.13,95%CI is(1.53,5.78);The ratio of Cu concentration is 0.39,95%CI is(0.39,0.63);The ratio of As concentration is 1.37,95%CI is(0.93,1.58).7.The concentration of maternal blood Ni and Cu in the control area showed an upward trend with the changes during pregnancy.Concentrations of maternal blood Ni,As in the contaminated areas and As in the control area did not change with the changes during pregnancy.Maternal blood As in the contaminated areas shows a decreasing trend with changes during pregnancy.Conclusions1.Exposure to high concentrations of As in pregnancy can result in fetal growth restriction.2.High concentrations of As in cord blood may cause adverse effects on the growth and development of newborns.3.The placental could have a barrier effect on Cu,but have no effective barrier to Ni and As. |
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