Fine structure of the human placenta in prolonged pregnancy. Preliminary report.

Placentas from 15 prolonged (is greater than 42 weeks), but otherwise normal pregnancies, and 8 normal-term placentas were studied. Placental villi from term placentas revealed intact syncytial and cytotrophoblast elements. All term placentas presented a minimal to mild degree of villous necrosis and deposition of fibrinoid material. Placental villi from cases of prolonged pregnancy presented a moderate to severe degree of necrosis in 11 of 15 placentas and a minimal to mild degree in 4 of 15 placentas. A moderate to severe degree of fibrinoid deposition was noted in 7 of 15 placentas, whilst 8 of 15 revealed a minimal to mild degree of deposition. The presence or absence of meconium was noted in the prolonged-pregnancy group and correlated with the above morphological features. Statistically, a correlation was found between prolonged pregnancy and necrosis (p is less than 0.001), prolonged pregnancy and fibrinoid deposition (p is less than 0.03) and between necrosis and deposition of fibrinoid (p is less than 0.05). There was no correlation between the incidence of meconium staining and the above parameters.