Placental Metal Concentrations in Relation to Maternal and Infant Toenails in a U.S. Cohort.

Metal contaminants cross the placenta, presenting a heightened risk of perturbing fetal development. Information about placental concentrations and transfer of multiple potentially toxic metals from low to moderate exposure is lacking. We measured concentrations of Cd, Pb, Hg, Mn, Se, and Zn in 750 placentas collected from women enrolled in the New Hampshire Birth Cohort Study and examined the correlation between elements, and profiles of potentially toxic metals (Cd, Pb, Hg, and Mn) stratified by nutrient concentrations (Zn and Se) using principal components analyses. We further examined the indirect effects of maternal metal concentrations on infant metal concentrations through placental metal concentrations using structural equation models. Placental metal concentrations were all correlated, particularly Zn and Mn, and Zn and Cd, and the principal component of metals differed by stratum of high versus low Zn and Se. Associations were observed between placenta and maternal toenail Se (ß = 63.49; P < 0.0001) and Pb (ß = 0.90; P < 0.0001) but not other metals. Structural equation models did not indicate any statistically significant indirect effects through placental metal concentrations. Placental metal concentrations may represent a distinct biomarker of metal exposure and adverse health impacts to the fetus, particularly those stemming from the placenta.

Collaborative maternity care: three decades of success at Dartmouth-Hitchcock Medical Center.

This article describes the development of our collaborative practice, discusses the barriers and challenges presented by the current health care environment, and identifies factors that would encourage the initiation and strengthening of a successful collaborative model in similar settings. Successful collaborative practice is more than just a practice model, or a set of items that, once checked off, will guarantee success. It is a process that is inextricably linked to the focus and dedication of all our clinicians to provide the best care possible for women.