The aim of this study was observe differences in the immunological distribution of the placental lactogene and IGF-1 receptor on free-chorionic villi, between studied groups and to relate the neonatal diagnosis of PEG with morphometric and immunohystochemical characteristics of the placenta. A total of, twelve placentas from AEG newborn and twelve from PEG newborn were obtained from the Maternity Ward of Temuco, Chile. H&E, Alcian blue and Masson's trichromic stains, as well as Hematoxilyn-PAS. In the immunoperoxidase technique, were used: 1) placental lactogen (polyclonal, dilution 1:200, NCL-PLP, Novocastra) 2) Insuline-1 like growth factor (monoclonal, dilution 1:200, NCL-GHR, No vocastra). Differences between PEG and AEG placentae in the immnunostaing for placental lactogen and IGF-1 receptor in the sincitial throphoblast were not observed.