Objective To determine mercury contents in pair in cord blood,fetal hair,placenta and maternal scalp hair,and to analyze the correlation among them and the effect of mercury exposure risk factors in the mercury contents of samples.Methods Puerperants in the hospital,who lived in the local area without history of major diseases during the whole pregnancy,were investigated by questionnaire composed to several health factors.Cord blood,fetal hair,placenta and maternal scalp hair of these puerperal and their neonates (polyembryony and birth defects excluded) were collected to determine mercury content in pairs.Results The mean mercury contents of cord blood,fetal hair,placenta and maternal scalp hair in 303 samples were 1.65 μg/kg,234.58 μg/kg,3.85 μg/kg,497.62 μg/kg,respectively.Fifty percentile of them were 1.72 μg/kg,252.24 μg/kg,3.98 μg/kg,508.88 μg/kg,respectively.There were direct correlations between mercury in cord blood and that in fetal hair,mercury in cord blood and that in placenta,mercury in cord blood and that in maternal scalp hair,mercury in fetal hair and that in placenta,mercury in fetal hair and that in maternal scalp hair,mercury in maternal scalp hair and that in placenta(all P ＜ 0.05).The mercury contents in cord blood,fetal hair and maternal scalp hair of those living nearby factories involved in mercury,higher intake fish during the pregnancy,firing coal and consumption of whiting cosmetics and smoking were determined as (2.24 ± 0.20) μg/kg,(315.65 ± 35.31) μg/kg and (663.53 ± 71.83) μg/kg.The mercury in those without the high risk factors mentioned above were(1.62 ± 0.16) μg/kg,(245.79 ± 28.21) μg/kg and (499.39 ± 47.72) μg/kg.There was a significant difference between 2 groups(all P ＜ 0.01).Conclusions In addition to control industrial pollution,pregnant women should avoid the above-mentioned high risk factors and pay more attention to health care during pregnancy.The mercury content in cord blood is highly correlated with the mercury in fetal hair,and that in placenta and in maternal scalp hair.The 2 kinds of detection both can achieve the purpose of monitoring mercury intrauterine exposure conditions.