Fact and fancy. What can we really tell from the placenta?

Considerable interest in the clinical significance of placental abnormalities has been fueled by malpractice claims when perinatal outcome is less than optimal. The pathologist must be aware of those placental lesions that may contribute to perinatal morbidity and mortality. This article reviews the abnormalities of placentation, placental weight, maternal uteroplacental blood flow, villous histological makeup, fetoplacental blood flow, the umbilical cord, and the membranes, as well as the problems of multiple pregnancy. The important contribution of abnormal uteroplacental blood flow to adverse perinatal outcome is emphasized, as is the need to determine the extent of placental damage when evaluating the contribution thereto of particular placental abnormalities.