The Effects Of Low-level Lead Exposure During Pregnancy On Fetal Bone Metabolism

Objectives:Studying the effects of low-level lead exposure during pregnancy on fetal bone metabolism.Methods:Choose 60 healthy pregnant women as the subjects. After the newborns were delivered after normal periods of gestation,they were divided into relatively high-level lead group >0.483 μmol/L(100μg/L)and low-level lead group <0.483 μmol/L(100μg/L),study the effects of lead exposure during pregnancy on the body development and bone metabolism index of the fetus. Collect 1ml of venous blood from the women at delivery,5ml of umbilical cord blood from the newborns,measure the blood lead,serum calcium,serum osteocalcin and alkaline phosphatase respectively. At the same time,study the correlation factors of each subject's blood lead level in the form of questionnaire and measure body weight,body height,head circumference,chest circumference of the newborns at birth.Results:(1)The cord blood lead level is positively related to those of the mothers' blood(r=0.812,P<0.001).(2)The newborns' cord blood lead level is negatively related to their serum osteocalcin(r=-0.489,P<0.001)and serum calcium level(r=-0.271,P<0.05),and positively related to alkaline phosphatase(r=0.296,p<0.05)。(3)The newborns' cord blood lead level is positively related to their body weight,body height,head circumference and chest circumference at birth,the effect on head circumference is statistically significant(r=-0.276,P<0.05).(4) Compare the relatively high-level lead group and low-level lead group:the serum osteocalcin level of the relatively high-level lead group(11.69±5.94ng/ml)is significantly lower than that of the low-level lead group(18.14±5.12ng/ml,P<0.001);the alkaline phosphatase of the relatively high-level lead group (172.54±55.72u/L)is significantly higher than that of the low-level lead group(133.43±52.05u/L,P<0.05);the geometric mean of serum calcium of the relatively high-level lead group2.13(0.3256±0.0417)mmol/L is significantly lower than that of the low-level lead group2.30(0.3594±0.0479)mmol/L,P<0.05;(5)The body weight of the newborns at birth in the relatively high-level lead group (3.18±0.2948kg)is lower than that of the low-level lead group(3.24±0.4019kg)but not statistically significant. body height of the relatively high-level lead group(50.66±0.9437cm)is lower than that of the low-level lead group (50.71±1.26cm); The head circumference of the relatively high-level lead group (34.11±1.02cm)is significantly lower than that of the low-level lead group(34.33±1.13cm),the chest circumference of the relatively high-level lead group(32.09±0.9169cm)is lower than that of the low-level lead group(32.19±0.9036cm), but not statistically significant. Conclusion:(1) Lead exposure during pregnancy is negatively related to the serum osteocalcin and serum calcium of the fetus, and positively related to alkaline phosphatase, all are statistically significant; The information above shows that the serum osteocalcin and serum calcium of the fetus in the relatively high-level lead group is lower than those in the low-level lead group; and alkaline phosphatase is higher than those in the low-level lead group,and is statistically significant. This indicates that lead exposure during pregnancy affects the process of bone formation. (2) Lead exposure during pregnancy is negatively related to the newborns' body weight,body height,head circumference and chest circumference, head circumference is statistically significant.This further indicates that the degree of lead's effects on fetus's bone metabolism has correlation with the exposure dose, low-level lead exposure during pregnancy could has disturbed the bone metabolism of the fetus.