Preterm birth (PTB) is responsible for over one million infant deaths annually worldwide. Often， the first and only indication of PTB risk is the onset of early labor. Thus， there is an urgent need for an early PTB risk diagnostic that is inexpensive， reliable， and robust. Here， we describe the development of a microchip electrophoresis (μCE) method for separating a mixture of six PTB protein and peptide biomarkers present in maternal blood serum. μCE devices were photografted with a poly(ethylene glycol) diacrylate surface coating to regulate EOF and reduce nonspecific analyte adsorption. Separation conditions including buffer pH， buffer concentration， and applied electric field were varied to improve biomarker peak resolution while minimizing deleterious effects like Joule heating. In this way， it was possible to separate six PTB biomarkers， the first μCE separation of this biomarker panel. LODs were also measured for each of the six PTB biomarkers. In the future， this μCE separation can be integrated with upstream maternal blood serum sample preparation steps to yield a complete PTB risk diagnosis microdevice.