Martha Maria Tellez-Rojo, Hector Lamadrid-Figueroa, Mauricio Hernández-Avila, David Bellinger, Adriana Mercado-García, Lourdes Schnaas, Donald Smith, Howard Hu
2004 Epidemiology  
BACKGROUND: The impact of prenatal lead exposure on neurodevelopment remains unclear in terms of consistency, the trimester of greatest vulnerability, and the best method for estimating fetal lead exposure. OBJECTIVE: We studied prenatal lead exposure's impact on neurodevelopment using repeated measures of fetal dose as reflected by maternal whole blood and plasma lead levels. METHODS: We measured lead in maternal plasma and whole blood during each trimester in 146 pregnant women in Mexico
more » ... We then measured umbilical cord blood lead at delivery and, when offspring were 12 and 24 months of age, measured blood lead and administered the Bayley Scales of Infant Development. We used multivariate regression, adjusting for covariates and 24month blood lead, to compare the impacts of our pregnancy measures of fetal lead dose. RESULTS: Maternal lead levels were moderately high with a first-trimester blood lead mean (± SD) value of 7.1 ± 5.1 µg/dL and 14% of values ≥ 10 µg/dL. Both maternal plasma and whole blood lead during the first trimester (but not in the second or third trimester) were significant predictors (p < 0.05) of poorer Mental Development Index (MDI) scores. In models combining all three trimester measures and using standardized coefficients, the effect of first-trimester maternal plasma lead was somewhat greater than the effect of first-trimester maternal whole blood lead and substantially greater than the effects of second-or third-trimester plasma lead, and values averaged over all three trimesters. A 1-SD change in first-trimester plasma lead was associated with a reduction in MDI score of 3.5 points. Postnatal blood lead levels in the offspring were less strongly correlated with MDI scores. CONCLUSIONS: Fetal lead exposure has an adverse effect on neurodevelopment, with an effect that may be most pronounced during the first trimester and best captured by measuring lead in either maternal plasma or whole blood. KEY WORDS: bone, IQ, lead, plasma, pregnancy, neurodevelopment. Environ Health Perspect 114:1730-1735 (2006). doi:10.1289/ehp.9067 available via http://dx.doi.org/ [Online 19 July 2006] CI, confidence interval. Each model is adjusted for infant's concurrent blood lead (24 months of age), sex, maternal age, current weight, height-for-age Z-score, and maternal IQ. Logarithmically transformed lead concentrations were used. Each line in the table represents a different model. a The arithmetic mean of log-blood lead or log-plasma lead using all available measurements.
doi:10.1097/00001648-200407000-00367 fatcat:2cbhnl3twzdzpfstun5nufnt7e