Contribution of plasma, placental, inflammatory and pro-resolving mediators in labor induction

The onset of labor is regulated by endocrine, nervous and immunological factors. This study was designed to determine the inflammatory and pro-resolving mediator levels in plasma and placenta of women undergoing labor induction in late-term pregnancy.

Healthy pregnant women admitted for delivery or labor induction were included. TNF, IL-1β, IL-6, IL-8, and IL-10 were quantified by ELISA in plasmatic and placental samples and Annexin A1 (ANXA1) in the placenta by Western Blotting, and immunofluorescence to CD15⁺ antibody. The data were analyzed using the Wilcoxon test and Spearman correlation. The p-value was significant when <0.05.

There was a higher concentration of IL-8 was found in the amniotic plaque (p = 0.042) and IL-10 (p < 0.001) in the trophoblast of patients with spontaneous labor. Greater ANXA1 density in the trophoblast was also observed in those with induction failure. There was a positive correlation of ANXA1 density in trophoblast induction duration with (r = 0.580) and with the IL-6 level in amniotic plaque (r = 0.517), and a positive correlation between labor duration and density of ANXA1 was identified in the trophoblast (r = 0.419). An increase was identified in CD15⁺ cell immunocapturing among the groups with spontaneous labor compared to the group with induction failure (p < 0.001).

The inflammatory process in labor involves both maternal and fetal participation. Induction failure is associated with higher levels of ANXA1 in the trophoblast.