Maternal plasma (MP) samples were collected from group 1: term not-in labor (TNIL, n=13); group 2: term in labor (TL, n= 11), group 3: preterm premature rupture of membranes (pPROM, n=8); and group 4: preterm birth (PTB, n=13). Exosomes isolated from plasma by differential density centrifugation followed by size exclusion chromatography were characterised by morphology (electron microscopy), quantity and size (nanoparticle tracking analysis and markers (western blot). A quantitative, information-independent acquisition (Sequential Windowed Acquisition of All Theoretical Mass Spectra [SWATH]) approach was used to determine the protein profile in exosomes. Ingenuity Pathway Analysis (IPA) determined pathways associated with the protein profile identified in exosomes.