Recent scientific research on lead suggests that: 1) cumulative stores in maternal bone may be mobilized during pregnancy, 2) an increase in blood lead even with low environmental exposures may raise blood pressure in adults, and 3) low to moderate exposures in early childhood increase the risk for developmental deficits that may be irreversible. Further, pregnancy-induced or aggravated hypertension is a serious complication occurring in 10 percent or more of pregnancies. A relationship of blood lead with blood pressure during pregnancy and with fetal growth and development is therefore hypothesized. A prospective study of 350 pregnant women (175 black and 175 white) is proposed using serial measurements of biomarkers: blood lead (PbB),bone mineral density, urinary hydroxyproline, and 25- and 1,25-dihydroxy vitamin D.
The aims are to determine: 1) Is third trimester blood pressure associated with PbB or its changes during pregnancy? 2) Is infant neurodevelopment associated with PbB and other biomarkers of potential fetal lead exposure? 3) Does gestational age, infant birth weight or birth length differ by maternal PbB or related biomarkers? 4) Do the higher lead levels of black women as compared with white women contribute to the higher mean blood pressures in pregnancy and the greater proportion of preterm births and lower birth weight infants observed among blacks? 5) Do PbB, bone density, urinary hydroxyproline, and 1,25-dihydroxy vitamin D change during pregnancy and how do these four interrelate? 6) How can cord lead and other biomarkers be combined into an index of cumulative fetal lead exposure? Women seeking prenatal care during their first trimester will be enrolled. In addition to measuring the biomarker, interviews will be conducted early and late in pregnancy to assess current and past lead exposure and dietary, lifestyle, occupational and psychosocial factors. At delivery, maternal and umbilical cord PbB will be measured, gestational age, birth weight and birth length will be recorded, and shortly thereafter, tests of neurodevelopment will be administered to one-half of the newborns. A subsequent investigation will follow up the children. Despite Federal restrictions on leaded gasoline, body burdens and environmental sources of lead may still pose considerable risks to the mother and fetus. If this study and other research confirms a relation of lead to increased blood pressure during pregnancy and to neurodevelopmental deficits, then voluntary public health screening for high-risk individuals and subsequent medical intervention may need to be considered.
| Harville, E W; Hertz-Picciotto, I; Schramm, M et al. (2005) Factors influencing the difference between maternal and cord blood lead. Occup Environ Med 62:263-9 |
| Harville, Emily W; Schramm, Margaret; Watt-Morse, Margaret et al. (2004) Calcium intake during pregnancy among white and African-American pregnant women in the United States. J Am Coll Nutr 23:43-50 |
| Promislow, Joanne H E; Hertz-Picciotto, Irva; Schramm, Margaret et al. (2004) Bed rest and other determinants of bone loss during pregnancy. Am J Obstet Gynecol 191:1077-83 |
| Hertz-Picciotto, I; Schramm, M; Watt-Morse, M et al. (2000) Patterns and determinants of blood lead during pregnancy. Am J Epidemiol 152:829-37 |
