Intrauterine growth retardation is an important cause of perinatal death. The etiology is predominantly renovascular-syndromes, chromosome or genetic anomalies, and idiopathic hypotrophy. The small for age baby is hypoxic and hypercapnic, with acidosis. Fetal circulation is redistributed to protect the brain. The type of retarded growth (well balanced? or not), its severity and its potential development can be evaluated by echographic examination, and means of Doppler study. The only treatment is fetal removal. The date of this removal is a compromise between the risk of fetal death or neurological consequences of prolonged hypoxia on the one hand, and of the risk of severe iatrogenic prematurity, or neonatal death, if removal is made at too young a gestational age. The only preventive treatment that has been evaluated is lowdose aspirin which, in at-risk patients, has reduced the risk by a factor of four to six.