[Placental morphometriological study on prolonged and delayed pregnancy and its relationship to pregnancy outcome]

To study the morphological characteristics of the placental villous vessels and uteroplacental spiral arteries in the prolonged and delayed pregnancy and its relationship to pregnancy outcome.

Placentae from 20 cases of prolonged pregnancy (PP), 15 cases of delayed pregnancy (DP), and 29 cases of normal term pregnancy (NTP) were examined by morphometriological feature image analysis.

Significant differences were found between PP and NTP groups (P < 0.05) in the following findings: the placental weights, the numbers of the placental villus with the syncytial knots, cytotrophoblasts, thickening of basal lamina, fibrinoid necrosis, vasculosyncytial membranes, and the diameter, perimeter and area of the villi the spiral artery wall thickening of the uteroplacental bed, and the incidences of the oligoamnios and amniotic fluid meconium staining. Significant differences of the villus perimeter and oligoamnios were only found between DP and NTP (all P < 0.05). There was no significant differences in the indices between PP and DP. As the pregnancy delayed and prolonged, the placental weights gradually decreased and the low Apgar score of neonates gradually increased.

After term pregnancy the placental function is gradually lowered especially in PP. The situations of the placenta, amniotic fluid, and fetus should be frequently monitored after 40 gestational weeks.