Causes and consequences of placental growth retardation.

Placental growth retardation caused 84 fetal and neonatal deaths per 100,000 births. Its frequency increased as mothers' diastolic blood pressure levels increased, an effect augmented by proteinuria. The perinatal deaths also increased with advancing maternal age, anemia, and poverty. Maternal weight gains were low in the involved pregnancies, and the fetuses and neonates who died had a pattern of growth retardation characteristic of fetal undernutrition. Microscopic abnormalities in the decidua and placenta were characteristic of inadequate perfusion of the placenta from the uterus. They included fibrinoid changes in the arteries and arterioles of the decidua, villous cytotrophoblastic hyperplasia, and an obliterative endarteritis in fetal stem arteries of the placenta.