Tehran University Medical Journal

Background: Lead poisoning has proven to be one of the most important environmental health problems among developing countries with both direct and indirect effects on human life. Lead is known to cross the blood-brain barrier and placenta, and accumulates in soft and hard tissues. Lead can be excreted in urine, stool, milk, sweat, nails and saliva. During pregnancy and lactation, lead is released from bones into the blood along with Ca²⁺. The toxic effects of lead on various human tissues have been studied extensively, but few studies have addressed its impact on fetal development during pregnancy. Blood levels of lead are higher in people living in lead-polluted regions. It has been reported that Tehran (central and southern parts) is the most problematic city in terms of lead poisoning.

Methods: From 86 sets of mothers and newborns in a non-polluted area of rural Rasht, Iran, we examined specimens of maternal blood, cord blood and colostrum (86×3=258) and specimens from 85 sets of mothers and newborns in a polluted area of Tehran, Iran (85×3=255) for lead levels using atomic absorption spectrophotometry (AAS) and analyzed the results by t-test, SPSS, and linear regression.

Results: The mean blood lead concentrations of mothers, cord blood of newborns and colostrum were 7.6±4.1, 5.9±3 and 4.2±2.5 μg/dl, respectively, in the non-polluted area and 9.1±8.4, 6.5±5.2 and 5.8±5.5 μg/dl, respectively, in the polluted area. The mean weights of the newborns in non-polluted and polluted areas were 3.2±0.5 kg and 3.2±4.5 kg, respectively.

Conclusions: Our data revealed an association between mean concentrations in blood lead of mothers and newborns and between mean concentrations of colostrum lead and newborn blood lead in both areas (p=0.01). There was no association between mean blood lead concentration of mothers with the weight of their newborns (p=0.89).