Decrease in birth weight in relation to maternal bone-lead burden

Department of Environmental Health , Harvard University, Cambridge, Massachusetts, United States
PEDIATRICS (Impact Factor: 5.3). 12/1997; 100(5):856-62. DOI: 10.1542/peds.100.5.856
Source: PubMed

ABSTRACT Birth weight predicts infant survival, growth, and development. Previous research suggests that low levels of fetal lead exposure, as estimated by umbilical cord blood-lead levels at birth, may have an adverse effect on birth weight. This report examines the relationship of lead levels in cord blood and maternal bone to birth weight.
Umbilical cord and maternal venous blood samples and anthropometric and sociodemographic data were obtained at delivery and 1-month postpartum. Blood-lead levels were analyzed by atomic absorption spectrophotometry. Maternal tibia and patella lead levels were determined at 1-month postpartum with use of a spot-source 109Cd K-X-ray fluorescence instrument. The relationship between birth weight and lead burden was evaluated by multiple regression with control of known determinants of size at birth.
Data on all variables of interest were obtained for 272 mother-infant pairs. After adjustment for other determinants of birth weight, tibia lead was the only lead biomarker clearly related to birth weight. The decline in birth weight associated to increments in tibia lead was nonlinear and accelerated at the highest tibia lead quartile. In the upper quartile, neonates were on average, 156 grams lighter than those in the lowest quartile. Other significant birth weight predictors included maternal nutritional status, parity, education, gestational age, and smoking during pregnancy.
Our results indicate that bone-lead burden is inversely related to birth weight. Taken together with other research indicating that lead can mobilize from bone into plasma without detectable changes in whole blood lead, these findings suggest that bone lead might be a better biomarker than blood lead. Because lead remains in bone for years to decades, mobilization of bone lead during pregnancy may pose a significant fetal exposure with health consequences, long after maternal external lead exposure has declined.

Download full-text


Available from: Howard Hu, Sep 19, 2014
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The heavy metals mercury, lead, and cadmium are toxicants, which are well-known to cross the placenta and to accumulate in fetal tissues. Prenatal exposure to mercury and lead poses a health threat particularly to the developing brain. Fetal exposures to lead and cadmium correlate with reduced birth weight and birth size. The placental passage of cadmium is limited suggesting a partial barrier for this metal. It is very likely that metallothionein is responsible for placental storage of the metals especially of cadmium. It is unclear, however, which proteins are involved in placental uptake and efflux of the metals and where the transporters are located at the placental barrier. Hence, only certain aspects of placental metal toxicokinetics are known so far. The metals have also been shown to adversely affect placental functions. Both metal-specific placental transfer and impairment of placental function can explain the relationships between prenatal metal exposures and adverse effects on intrauterine growth and (neuro)development.
    Wiener Medizinische Wochenschrift 05/2012; 162(9-10):201-6. DOI:10.1007/s10354-012-0074-3
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cumulative prenatal lead exposure, as measured by maternal bone lead burden, has been associated with smaller weight of offspring at birth and 1 month of age, but no study has examined whether this effect persists into early childhood. We investigated the association of perinatal maternal bone lead, a biomarker of cumulative prenatal lead exposure, with children's attained weight over time from birth to 5 years of age. Children were weighed at birth and at several intervals up until 60 months. Maternal tibia and patella lead were measured at 1 month postpartum using in vivo K-shell X-ray fluorescence. We used varying coefficient models with random effects to assess the association of maternal bone lead with weight trajectories of 522 boys and 477 girls born between 1994 and 2005 in Mexico City. After controlling for breast-feeding duration, maternal anthropometry, and sociodemographic characteristics, a 1-SD increase in maternal patella lead (micrograms per gram) was associated with a 130.9-g decrease in weight [95% confidence interval (CI), -227.4 to -34.4 g] among females and a 13.0-g nonsignificant increase in weight among males (95% CI, -73.7 to 99.9 g) at 5 years of age. These associations were similar after controlling for concurrent blood lead levels between birth and 5 years. Maternal bone lead was associated with lower weight over time among female but not male children up to 5 years of age. Given that the association was evident for patellar but not tibial lead levels, and was limited to females, results need to be confirmed in other studies.
    Environmental Health Perspectives 06/2011; 119(10):1436-41. DOI:10.1289/ehp.1003184 · 7.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The heavy metals lead (Pb) and mercury (Hg) are ubiquitous environmental pollutants with high neurotoxic potential. We aimed to compare perinatal Pb and Hg concentrations and to explore the potential association between Pb and Hg exposure and newborn anthropometry. Pregnant women were recruited in 2005 at the General Hospital Vienna for participation in this longitudinal study. Pb and Hg concentrations were measured in maternal blood and hair, placenta, cord blood, meconium, and breast milk of 53 mother-child pairs by CV-AAS, GF-AAS, and HPLC-CV-ICPMS. We conducted bivariate analyses and categorical regression analysis (CATREG) to evaluate the determinants of Pb and Hg exposure, and of infant anthropometry. Median Pb and total Hg contents were low, i.e., 25 μg/L (maternal blood-Pb), 13 μg/L (cord blood-Pb), 0.7 μg/L (maternal blood-Hg), and 1.1 μg/L (cord blood-Hg). Hg levels in maternal and fetal tissues were frequently correlated (r>0.3, P<0.05, respectively). Regarding Pb, only maternal blood and cord blood concentrations correlated (P=0.043). Cord blood levels indicated higher Hg exposure but lower Pb exposure relative to maternal blood contents. Adjusted CATREG models indicated the significant predictors of birth length (placenta-Pb, gestational length, meconium-Pb), birth weight (placenta-Pb, gestational length, maternal blood-Pb), and head circumference (maternal education, maternal height). Besides one significant correlation between maternal hair Hg and birth length, the mercury levels were not associated with newborn anthropometry. Our data implicate that different modes of action may exist for placentar transfer of Pb and Hg as well as that low Pb exposure levels can result in lower birth weight. The findings related to newborn anthropometry need to be confirmed by the examination of larger study groups. Further research is needed to clarify the mechanisms of Pb and Hg transfer via the placenta, and to explore how prenatal Pb exposure is related to intrauterine growth.
    Science of The Total Environment 11/2010; 408(23):5744-9. DOI:10.1016/j.scitotenv.2010.07.079 · 4.10 Impact Factor