RESUMO
Serum concentrations of alpha-2-macroglobulin (alpha 2M) were measured in cord blood from neonates born in Alabama, USA and in Guatemala. Results indicate an inverse relationship between cord serum alpha 2M concentrations and birth weight of newborns in both locations. Infants with lower birth weight had higher cord serum alpha 2M concentrations as compared to those with higher birth weight. The results of the present study using cord serum are similar to those in our previous reports indicating an inverse relationship between maternal serum alpha 2M concentrations and birth weight. This distinctive and reproducible association between alpha 2M concentrations and fetal size in maternal as well as cord blood samples warrants further investigations to determine the mechanism of this relationship.