The intra-uterine components of labor, namely, myometrial contractility, cervical
ripening, and decidua/membrane activation, have been extensively characterized and
involve a local pro-inflammatory milieu of cellular and soluble immune mediators.
Targeted profiling has demonstrated that such processes extend to the intra-amniotic
space, yet unbiased analyses of the proteome of human amniotic fluid during labor
are lacking. Herein, we utilized an aptamer-based platform to characterize 1,310 amniotic
fluid proteins and found that the proteome undergoes substantial changes with term
labor (251 proteins with differential abundance, q < 0.1, and fold change > 1.25).
Proteins with increased abundance in labor are enriched for immune and inflammatory
processes, consistent with prior reports of labor-associated changes in the intra-uterine
space. By integrating the amniotic fluid proteome with previously generated placental-derived
single-cell RNA-seq data, we demonstrated the labor-driven upregulation of signatures
corresponding to stromal-3 and decidual cells. We also determined that changes in
amniotic fluid protein abundance are reflected in the maternal plasma proteome. Collectively,
these findings provide novel insights into the amniotic fluid proteome in term labor
and support its potential use as a source of biomarkers to distinguish between true
and false labor by using maternal blood samples.
