Lead Toxicity: Its Effects on Fetal and Infant Development Essay

Lead Toxicity: Its Effects on Fetal and Infant Development Lead toxicity has been an area of unending research in recent years. There have been positive and negative correlation’s relating its toxic effects to both child developmental deficiencies and adult regression problems. This review will focus on the problems associated with the children. It will discuss various routes of entry of lead into the child’s system, both prenatally and postnatally, the mechanisms employed by lead to cause the dysfunction’s, and some of the neurological deficits believed to be caused by the lead exposure. The development of a child begins in utero and continues following birth; thus both of these time frames must be examined as possible periods of lead intoxication. During development, the fetus is at the mercy of its mother. If the mother has high blood lead levels during pregnancy, the developing fetus will have the same. This is due to the lack of a transplacental barrier to lead. Thus, the maternal levels are consistently equal to fetal levels throughout pregnancy. The mode of transport is not clearly understood. However, it has been suggested that it is a matter of simple diffusion for several reasons (1). First, is the close quantitative relationship between maternal and fetal blood lead levels. Second, is the experimentally modeled linear relationship between the transfer of lead from the mother to the fetus and the umbilical blood flow rate. An increase in blood flow rate coupled with the increased surface area of the placental barrier, 2 m2 to 11 m2, over the gestational peri od increases the transplacental diffusion (1). With this direct correlation in mind, it then becomes important to discuss possible sources of increased mater... ...991; 13: 203-211. 4.Bressler, J. P. and Goldstein, G.W. "Mechanisms of Lead Toxicity." Biochemical Pharmacology. 1991; 41: 479-84. 5. Dietrich, K. N. "Human Fetal Lead Exposure: Intrauterine Growth, Maturation, and Postnatal Neurobehavioral Development." Fundamental and Applied Toxicology. 1991; 16: 17-19. 6. Bellinger, D., Leviton, A., and Sloman, J. "Antecedents and Correlates of Improved Cognitive Performance in Children Exposed in Utero to Low Levels of Lead." Environmental Health Perspectives. 1990; 89: 5-11. 7. Bhattacharya, A., Shukla, R., Bornschein, R. L., et.al. "Lead Effects on Postural Balance of Children." Environmental Health Perspectives. 1990; 89: 35-42. 8. Ernhart, C. B. and Greene, T. "Low-Level Lead Exposure in the Prenatal and Early Preschool Periods: Language Development." Archives of Environmental Health. 1990; 45: 342-354. Lead Toxicity: Its Effects on Fetal and Infant Development Essay Lead Toxicity: Its Effects on Fetal and Infant Development Lead toxicity has been an area of unending research in recent years. There have been positive and negative correlation’s relating its toxic effects to both child developmental deficiencies and adult regression problems. This review will focus on the problems associated with the children. It will discuss various routes of entry of lead into the child’s system, both prenatally and postnatally, the mechanisms employed by lead to cause the dysfunction’s, and some of the neurological deficits believed to be caused by the lead exposure. The development of a child begins in utero and continues following birth; thus both of these time frames must be examined as possible periods of lead intoxication. During development, the fetus is at the mercy of its mother. If the mother has high blood lead levels during pregnancy, the developing fetus will have the same. This is due to the lack of a transplacental barrier to lead. Thus, the maternal levels are consistently equal to fetal levels throughout pregnancy. The mode of transport is not clearly understood. However, it has been suggested that it is a matter of simple diffusion for several reasons (1). First, is the close quantitative relationship between maternal and fetal blood lead levels. Second, is the experimentally modeled linear relationship between the transfer of lead from the mother to the fetus and the umbilical blood flow rate. An increase in blood flow rate coupled with the increased surface area of the placental barrier, 2 m2 to 11 m2, over the gestational peri od increases the transplacental diffusion (1). With this direct correlation in mind, it then becomes important to discuss possible sources of increased mater... ...991; 13: 203-211. 4.Bressler, J. P. and Goldstein, G.W. "Mechanisms of Lead Toxicity." Biochemical Pharmacology. 1991; 41: 479-84. 5. Dietrich, K. N. "Human Fetal Lead Exposure: Intrauterine Growth, Maturation, and Postnatal Neurobehavioral Development." Fundamental and Applied Toxicology. 1991; 16: 17-19. 6. Bellinger, D., Leviton, A., and Sloman, J. "Antecedents and Correlates of Improved Cognitive Performance in Children Exposed in Utero to Low Levels of Lead." Environmental Health Perspectives. 1990; 89: 5-11. 7. Bhattacharya, A., Shukla, R., Bornschein, R. L., et.al. "Lead Effects on Postural Balance of Children." Environmental Health Perspectives. 1990; 89: 35-42. 8. Ernhart, C. B. and Greene, T. "Low-Level Lead Exposure in the Prenatal and Early Preschool Periods: Language Development." Archives of Environmental Health. 1990; 45: 342-354.