Maternal and cord blood metal concentrations and low birth weight--a case-control study.

There has been speculation on the possible role of trace metals in contributing to the occurrence of low birth weight, but few data are available for most metals. Twenty-five women giving birth to infants weighing between 1500 and 2500 g (cases) and 50 women giving birth to infants weighing more than 2500 g (controls) were studied. The cases and controls were matched for age +/- 4 years), race, and socioeconomic status. Cord blood and maternal blood collected at delivery were analyzed by atomic absorption spectrophotometry for calcium, magnesium, copper, lead, and iron. Significant differences between the mean blood metal concentrations of the low birth weight and control groups were found for calcium (P less than 0.001) and iron (P less than 0.05) in the maternal blood samples and for calcium (P less than 0.001) and iron (P less than 0.01) in the cord blood samples. All concentrations were lower in the low-birth weight group except for the maternal iron level. No significant differences between the low birth weight and control groups were found for copper, lead, and magnesium in either maternal or cord blood.