Physiology and management of intrauterine growth retardation: a biologic approach with fetal blood sampling.

Intrauterine growth retardation is a major contributor to perinatal mortality and morbidity. The most important obstetric problem is to determine which fetuses are well in utero and which are at risk of irreversible damage or severe and prolonged neonatal morbidity. The optimal timing of delivery is at present made by subjective assessment of clinical variables. We present hematologic and biochemical values obtained by fetal blood sampling of 24 idiopathic fetuses with intrauterine growth retardation to give objective information on which to base clinical management. The results show that there is stimulation of erythropoiesis as well as evidence of red blood cell destruction and liver damage. In many cases there is acute decompensation with acid base abnormalities in a setting of chronic hematologic and biochemical changes.