Insights into the multifactorial nature of preterm birth: proteomic profiling of the maternal serum glycoproteome and maternal serum peptidome among women in preterm labor

Objective: The purpose of this study was to identify peptide classifiers that predict spontaneous preterm birth (SPTB) among women in preterm labor (PTL) and to demonstrate specific protein pathways that are activated in PTL. Study Design: Serum from 110 women with PTL between 20 weeks and 33 weeks 6 days of gestation was subjected to glycoprotein purification, matrix-assisted laser desorption ionization time-of-flight mass spectrometry peptide profiling, 2-dimensional liquid chromatography tandem mass spectrometry, and pathway analysis. Women were divided into 2 groups: delivery at <34 weeks' gestation (SPTB group) and delivery at ≥34 weeks' gestation (PTL group). Results: Twenty-three peptide masses were identified that discriminated PTL from SPTB in 97% of cases. Fifty-two proteins were present differentially between PTL and SPTB; 48 of 52 proteins were classified into 1 of 4 functional pathways that were involved with PTL: (1) complement/coagulation cascade, (2) inflammation/immune response, (3) fetal-placental development, and (4) extracellular matrix proteins. Conclusion: Among women in PTL, proteomic analysis of serum peptides and glycoproteins classifies women who will deliver preterm and identifies specific protein pathways at work among individuals with "idiopathic" PTL.