Factors influencing the difference between maternal and cord blood lead

Abstract

Aims: To determine the factors that affect why some infants receive higher exposures relative to the mother's body burden than do others. Methods: A total of 159 mother-infant pairs from a cohort of women receiving prenatal care at MageeWomens Hospital in Pittsburgh, PA from 1992 to 1995 provided blood samples at delivery for lead determination. The difference between cord and maternal blood lead concentration (PbB) and a dichotomous variable indicator of higher cord than maternal PbB, were examined as indicators of relative transfer. Women were interviewed twice during the pregnancy about lifestyle, medical history, calcium nutrition, and physical activity. Results: Higher blood pressure was associated with relatively greater cord compared with maternal PbB, as was maternal alcohol use. Sickle cell trait and higher haemoglobin were associated with a lower cord relative to maternal blood lead PbB. No association was seen with smoking, physical exertion, or calcium consumption. Conclusion: While reduction in maternal exposure will reduce fetal exposure, it may also be possible to mitigate infant lead exposure by reducing transfer from the pregnant woman. Interventions aimed at reducing blood pressure and alcohol consumption during pregnancy may be useful in this regard. E xposure to lead causes developmental problems. Although postnatal and childhood exposure can have effects at low concentrations, 1 children who have been exposed to lead in utero may also suffer from deficits in development (such as intelligence, information processing, memory, and verbal skills), 2-7 growth, 8 9 and behaviour.10 11Because lead is incorporated into the bone matrix where it is retained for decades, 12 13 prenatal exposure to lead also contributes to an earlier and cumulatively greater body burden.14 15Maternal and infant blood lead levels (PbB) are highly correlated across a wide range of exposure levels, [16][17][18] so the most obvious sources of variation in fetal lead dose are those that affect the maternal PbB. Some sources of infant PbB reflect direct maternal exposure, such as occupational lead exposure, exposure to lead paint, or use of lead glazed ceramics.19 Since cigarette smoke contains lead, 20 21 smoking and passive smoking could fall into this category as well. 22Other factors associated with infant PbB may reflect a lifestyle associated with increased environmental exposure to lead. Maternal coffee consumption and alcohol use, 22 23 higher blood pressure, 24 25 and seasonal patterns 26-28 are such variables.For over 30 years, it has been recognised that lead freely crosses the placenta via diffusion.29 30 It has generally been assumed that there is no general enhancement or barrier to transfer. 31 However, factors besides the maternal lead exposure and PbB also appear to affect the concentration in fetal blood. Although maternal PbB is on average about 30% higher than the infant's, in most studies approximately one quarter of the infants have PbB higher than their mothers. [32][33][34][35][36] Rothenberg and co...

Cadmium, Lead, and Selenium in Cord Blood and Thyroid Hormone Status of Newborns

“…When compared with the previously reported concentrations in cord whole blood in other countries (Table 4) [16][17][18][19][20][21][22][23][24][25][26][27][28][29], higher Se concentration and lower Pb concentration was noted in this study. No clear-cut threshold for Se deficiency has been established, 100 ng/g might be a candidate level because above this level correlation with glutathione peroxidase activity diminishes [30].…”

Changes in low levels of lead over the course of pregnancy and the association with birth outcomes

“…Approximately 90% of lead is stored in bone creating an important endogenous source of fetal exposure [6]. Maternal blood lead level and infant blood lead are highly correlated [7] with umbilical cord lead estimated to be approximately 85% of the maternal lead level [8,9].…”

Chronic Ayurvedic medicine use associated with major and fatal congenital abnormalities

“…Umbilical cord whole blood lead collected at delivery has been widely used as a measure of fetal exposure (Harville et al 2005;Satin et al 1991;Scanlon 1971;Rothenberg et al 1996;). Lead readily crosses the placenta by passive diffusion (Goyer 1990;Silbergeld 1986) and fetal blood lead concentration is highly correlated with maternal blood lead concentration (Goyer 1990).…”

“…Numerous studies suggest that maternal blood lead and umbilical cord lead levels, measured concurrently at delivery, are highly correlated (Baghurst et al 1991;Harville et al 2005;Rothenberg et al 1996), suggesting a near-perfect linear relationship. Most data indicate that umbilical cord lead is approximately 0.85 of maternal blood lead at parturition (Carbonne et al 1998;Goy er 1990;).…”