Neonates blood lead levels

In the study of the toxic element status of healthy Austrian women (n = 51) and their new-born babies a significant correlation between maternal and neonatal blood lead level (P < 0.001) was found. The mean concentration of lead was 3.7 (SD 1.27) xg/dl in whole blood of the mothers, 2.63 (SD 1.16) fJig/dl in whole blood of the new-borns, and 35.8 (SD 15.0) jLg/l in breast milk (Plockinger et al., 1993). 

NS (general population) Developmental No association between blood lead levels and birth weight, gestational age, or other neonatal size measures 3-55 Factor-Litvak et al. 1991 Greene and Ernhart 1991... 

Kotok (1972) found that the developmental deficiencies in a group of asymptomatic children with elevated blood lead levels were identical to those of a control group similar in age, sex, environment, neonatal condition and, importantly, incidence of pica. Moreover, these deficiencies could be correlated with inadequacies in the environment. Because a somewhat insensitive measure of development was used (the Denver Developmental Screening Test), and the groups were small, this study could not exclude the possibility of minimal neurological damage. Its main conclusion was that the observed developmental deficiencies could not be considered to be due to lead toxicity. 

Chronic exposure during the neonatal period in the rat. Pharmacology, 14, 435 Kostas, J., McFarland, D. J. and Drew, W. G. (1978). Lead-induced behavioral disorders in the rat Effects of amphetamine. Pharmacology, 16, 226 Kostial, K., Simonvic, I. and Pisonic, M. (1971). Lead absorption from the intestine of newborn rats. Nature (London), 233, 564 Kostial, K. and Vouk, V. B. (1957). Lead ions and synaptic transmission in the superior cervical ganglion of the cat. Br. J. Pharmacol., 12, 219 Kotok, D. (1972). Development of children with elevated blood lead levels A controlled study. J. Pediatr., 80, 57... 

First, the possibility will be considered that some unmeasured or undermeasured confounding conditions may be particularly crucial to gestational lead exposure and to neonatal outcome measures. The second possibility to be considered is whether discrepancies between studies with respect to correction of blood lead level (PbB) for haematocrit percent (Hct%) may be related to discrepant results. Data from our Cleveland study will be used to illustrate some of these issues. While this commentary is limited to neonatal outcome measures, the issues raised are also relevant to prospective analyses relating foetal lead exposure to later development. 

Evidence from several recent prospective and retrospective studies indicates that lead may be psychoteratogenic at relatively low levels of foetal exposure. In the present interim study, lead measured in whole blood during the prenatal (maternal blood lead) and neonatal periods was found to be inversely related to a complex of sensorimotor developmental indices at 6 and 12 months. Prenatal blood lead was also related to lower birth weight, which in turn was related to poorer sensorimotor performance in infants during the first year. These adverse effects were observed at levels of lead exposure common in pregnant women in the United States, Europe, and other developed areas. 

Sokol, R.J., Martier, S. and Emhart, C.B. (1985). Identification of alcohol abuse in the prenatal clinic. In Early Identification of Alcohol Abuse. NIAAA Research Monograph-17, NIAAA Wesenberg, R.L. (1978). Neonatal thick blood" syndrome. Hosp. Pract., May, 137-145 Wibberley, D.G., Khera, A.K., Edwards, J.H. and Rushton, D.I. (1977). Lead levels in human placentae from normal and malformed births. ]. Med. Genet., 14, 339-345 Wirth, F.H., Goldberg, K.E. and Lubchenco, L.O. (1979). Neonatal hyperviscosity I. Incidence. Pediatrics, 63, 833-836... 

Once absorbed, foreign compounds may react with plasma proteins and distribute into various body compartments. In both neonates and elderly human subjects, both total plasma-protein and plasma-albumin levels are decreased. In the neonate, the plasma proteins may also show certain differences, which decrease the binding of foreign compounds, as will the reduced level of protein. For example, the drug lidocaine is only 20% bound to plasma proteins in the newborn compared with 70% in adult humans. The reduced plasma pH seen in neonates will also affect protein binding of some compounds as well as the distribution and excretion. Distribution of compounds into particular compartments may vary with age, resulting in differences in toxicity. For example, morphine is between 3 and 10 times more toxic to newborn rats than adults because of increased permeability of the brain in the newborn. Similarly, this difference in the blood-brain barrier underlies the increased neurotoxicity of lead in newborn rats. 

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