Placental factor in spontaneous term labor in uncomplicated pregnancy

Objectives: To investigate the placental role in uncomplicated pregnancies and spontaneous term labor. Methods: Placentas were retrieved from women with uncomplicated pregnancies and compared between those with spontaneous term labor to those with elective cesarean delivery without labor. Placentas were analyzed for lesions consistent with maternal circulation abnormalities, lesions consistent with fetal thrombo-occlusive disease and inflammatory lesions, maternal or fetal responses. Results: The study included 139 pregnancies, 76 with term spontaneous deliveries (cases) and 63 with term elective cesarean deliveries (controls). Maternal age, gravidity, parity and BMI were significantly lower in the study group, but gestational age was higher as compared with the control group. Higher rate of maternal inflammatory lesions was observed in the study group compared to the control group, 21 vs. 1.6%, respectively, p = 0.001. No differences were observed in vascular lesions or in fetal inflammatory lesions between the groups. Conclusion: Placental maternal inflammatory changes play a role in spontaneous term labor, different from the involvement of the fetal compartment and placental vascular component in preterm labor.