RESUMO
Objective To study the relationship between the low level lead exposure of pregnant woman and the gestational age of fetus. Methods The peripheral blood and the umbilical blood samples were collected from 1 000 healthy puerperants and their newborns. The puerperants were divided into three groups according to the blood lead levels: very low-level group(0.483 ?mol/L). Results The rate of premature labor was 9.40% in the very low-level group, 14.07% in the low-level group and 23.81% in the high-level group respectively. The blood lead level of puerperants had a positive correlation with the umbilical blood lead of newborns. The umbilical blood lead of premature was higher than that of mature. As the blood lead level of the pregnants increased, the gestational age shortened and the probability of low age premature increased. Conclusion As for the toxicity of lead to the fetus, there is no a threshold. Low level lead exposure of the pregnant woman is one of the causes of premature labor.