Objective To investigate the change of blood lead concentration and possible influential factors during pregnancy in a lead-polluted area.
Methods It was a prospective cohort study. Pregnant women were recruited as participants and all respondents signed an informed consent before participating in the study. Blood lead concentration in different phase of pregnancy(early pregnancy and late pregnancy) was examined to identify the status of participants' lead exposure. Besides, in terviews were conducted among participants to collect the information of factors related to their blood lead concentration with questionnaire.
Results The geometric mean of blood lead concentration of participants was 0.15 μmol/L in early pregnancy and it increased to 0.19 μmol/L in late pregnancy. Statistically significant difference (P<0.05)was found between the two stages. The multivariate analysis showed that, the logarithm of blood lead concentration of pregnant women who ate vegetables everyday was 0.16 in the early stage and 0.15 in the late stage of pregnancy, both higher than those who didn't eat vegetables everyday. The lo garithm of blood lead concentration of those who had a history of heavy mental exposure before pregnancy was 0.12, higher than those who didn't in early pregnancy. The logarithm of blood lead concentration of pregnant women with higher educational level was 0.09, lower than those with lower educational level in late pregnancy.
Conclusion The blood lead concentration of pregnant women changes during the pregnancy. Eating lead-contaminated vegetables and having a history of heavy metal exposure seem to be significant factors related to pregnant women's blood lead concentration in early pregnancy. In late pregnancy, eating leadcontaminated vegetables and participants' educational degree are two significant factors related to blood lead concentration.
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