Causes of the excessive rates of perinatal mortality and prematurity in pregnancies complicated by maternal urinary-tract infections.

The study was undertaken to determine the causes of the more frequent pre-term deliveries, fetal and neonatal deaths associated with maternal urinary-tract infections during pregnancy. The combined perinatal mortality rate for eight common placental and fetal disorders was 42 per thousand births in the infected vs. 21 per thousand in the noninfected, owing to a greater mortality from noninfectious placental and fetal disorders in the gestations with the urinary-tract infections (P less than 0.001). All the mortality excess took place when the urinary-tract infections occurred within 15 days of delivery. Death rates were highest when the urinary-tract infections coexisted with maternal hypertension and acetonuria.Hydramnios, amniotic-fluid bacterial infections and abruptio placentae were responsible for two thirds of the more frequent preterm deliveries in the pregnancies complicated by urinary-tract infections.