The evaluation of the effect of maternal blood lead concentration on the incidence of delivery of low birth weight neonates

Low birth weight of the neonates is one of the most common problems in neonatology and its incidence is 7.6% of all live births. Several risk factors including lead exposure during pregnancy have been considered as predisposing factors. Thus, we decided to study the relationship between maternal blood lead level and the incidence of delivery of the low birth weight neonates. In this case-control study, 40 mothers with low birth weight newborns (<2500gr) and 40 mothers with normal weight newborns (>2500gr) were considered as case and control groups respectively and admitted in Emam Reza Hospital, Mashad Medical University, in 2005. Blood lead level was measured by use of atomic absorption spectrophotometry. There were no significant differences in the mean values of age, BMI and place of residence between the 2 groups (P values were 0.17 for age, 0.9 for place of residence). Mean neonatal weight in case and control groups were 2001±437gm and 3156±422.7gm respectively. Mean maternal blood lead level was 144.6±28.5 µg/lit. Mean maternal blood lead level in control and case groups were 124.6±17.5 µg/lit and 104.9±26.4 µg/lit respectively which showed a significant difference (P=0.02). In addition, blood lead level in 68.8% of mothers was higher than 100. Blood lead levels in the mothers of our study were significantly higher than those of other studies in other countries. Although elevated blood lead level during pregnancy did not lead to low birth weight deliveries, it may give rise to nervous system disorders in the future.