Determinants of lead level in umbilical cord blood.

Lead levels were measured by atomic absorption spectrophotometry in umbilical cord blood samples of 205 consecutively born neonates and venous blood in 62 of the mothers. The mean (+/- SD) cord blood lead level was 4.7 +/- 12.1 microg/dL. In the sub sample of 62 mother-baby pairs, the mean (+/- SD) cord blood lead levels were 1.6 +/- 2.5 microg/dL and 2.0 +/- 2.1 microg/dL, respectively. According to CDC risk categories, 92% babies were in Class I of which 87% had lead levels below 5 microg/dL. The mean (+/- SD) birthweight in <5 microg/dL category was 2640 +/- 445 grams as compared to 2617 +/- 408 grams in >5 microg/dL category. The mean (+/- SD) gestational ages were 39.1 +/- 2.0 weeks and 38.1 +/- 2.0 weeks, respectively in the two groups (P=0.014). On multivariate linear analysis, lower gestational age significantly correlated with higher cord blood lead level.