In this study, we aimed to assess the determining role of foetal fibronectin (FFN) and plasminogen activator inhibitor type (PAI-1) levels in the antenatal prediction of placenta accreta spectrum in cases with risk factors for placenta accreta spectrum. Singleton live pregnancies with placenta previa or low-lying placenta within 32–34 weeks of gestation were included in the study. The cases were divided into two groups after delivery as those with PAS and those with normal placentation. 54 cases diagnosed with placenta previa or low-lying placenta were included in the study. 17 of the cases underwent peripartum hysterectomy due to placenta accreta spectrum. 37 cases with normal placentation underwent caesarean delivery. Foetal fibronectin (p:.03) and PAI-1 (p:.02) levels were determined to be significantly different between cases with placenta accreta spectrum and cases with normal placentation. AUC for foetal FFN was calculated to be 0.69, while the AUC for, PAI-1was 0.66. Results for both FFN and PAI-1 were not found useful enough for the diagnosis of PAS. IMPACT STATEMENTWhat is already known on this subject? We lack biomarkers which can identify placenta accreta spectrum. What do the results of this study add? Maternal plasma levels of FFN and PAI-1 significantly altered in PAS What are the implications of these findings for clinical practice and/or future research? If multiple of median values of FFN and PAI-1 levels in maternal blood are determined in future studies, it can be used in the antenatal diagnosis of PAS cases.