Pathologic analysis of preterm delivery placentas.

198 preterm delivery placentas of 28 weeks to less than 37 weeks pregnancy were analyzed. Gross examination revealed that the differences of placenta previa and low implantation (2.91%), bipartate placenta and rupture of marginal sinus (0.97% respectively), large placenta (2.91%), short cord (4.85%), velamentous insertion of cord (3.88%), etc in comparison with those of term delivery placentas were statistically significant. Microscopic examination of 165 placentas showed that in 19 cases (11.52%) of infection of membranes and umbilical vessels, 11 were due to premature rupture of membranes or cervical interventions and 8 to preterm delivery. Among 72 cases of PIH, 65 (90.28%) had arteriopathy of decidua capsularis. 18 cases (25%) which had not been diagnosed clinically as PIH were found to be neglected after discovery of arteriopathy of decidua capsularis by pathologic examination. Placental examinations showed that preterm delivery may be attributable to the factors of placenta, amniotic fluid and umbilicus. 20 cases (27.78% of total PIH) of premature rupture of membranes were complicated by PIH. Whether the cases of decidual arteropathy are liable to have rupture of membranes awaits further investigation.