Objective: to verify changes in placental morphology of small for gestational age newborns, considering that the occurrence of placental alterations is more frequent in small for gestational age (SGA) infants than in appropriate for gestational age (AGA) infants. Methods: fifty SGA newborns were included in a cross-sectional study, which involved gross anatomy and light microscopy of placenta, membranes and umbilical cord. An equal size sample of randomized AGA newborns was used. All children were born at Maternidade Terezinha de Jesus, Juiz de Fora - MG, between February and November, 1996. After an informed consent was given by the mothers, the newborns were weighted at birth with assessment of length and head circumference. Every child's placenta, membranes and umbilical cord were sent to the laboratory of histology and embryology of the Department of Morphology of Universidade Federal de Juiz de Fora and Department of Pathology and Forensic Medicine of Universidade Federal de Minas Gerais. Results: placentas of SGA newborns differed significantly with greater incidence of chorioamniotitis, placental infarction, extensive perivillous fibrin deposition and multiple foci of parabasal chronic villitis. They were also lighter and had smaller diameters. Placentary index (placental weight/newborn's weight ratio) was also significantly greater, indicating that although both placenta and small for gestational age newborn presented low weight, placentas impairment was smaller. Conclusions: placentas of small for gestational age newborns differed significantly if compared to those of adequate gestational age.
small for gestational age infant; fetal growth retardation; placenta
