The present invention relates to a method for determining risk of preterm birth (PTB) in a pregnant individual. The method comprises measuring in a biological sample obtained from the pregnant individual, levels of biomarkers AFP and free hCGbeta, and at least one biomarker selected from FSTL3, sTNFR1, PIGF2, Activin A, uE3 and sP-selectin and optionally cervical length; or levels of biomarkers AFP and free hCGbeta and cervical length, and determining a relative risk of the pregnant individual developing PTB. The invention relates also to a kit, apparatus and system for predicting risk of PTB.