Objective:To find predictive value of sFlt-1 and PlGF in preeclampsia and placenta accreta spectrum (PAS), evaluate the sFlt-1/PlGF ratio in both conditions, and determine its diagnostic accuracy.Design:Prospective observational study.Setting:Department of Obstetrics and Gynaecology, Dayanand Medical College & Hospital (DMCH), Ludhiana.Population or Sample:A total of 200 antenatal patients between 20–37 weeks of gestation.Methods:A one-year prospective observational study (June 2023–June 2024) was conducted at a Single- Center Tertiary Care Hospital. Serum sFlt-1 and PlGF levels were measured using electrochemiluminescence immunoassay (ECLIA) on COBAS E411, and the sFlt-1/PlGF ratio was calculated. Patients were monitored for development of preeclampsia, PAS, and maternal-fetal outcomes.Main Outcome Measures:Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy of the sFlt-1/PlGF ratio for preeclampsia and PAS.Results:For preeclampsia (Group A), the sFlt-1/PlGF ratio cut-off of 77.65 yielded a sensitivity of 80.7%, specificity of 91.3%, and diagnostic accuracy of 88.0%. PPV was 80.7% and NPV was 91.3%. For PAS (Group B), the same cut-off showed sensitivity of 87.5%, specificity of 51.97%, PPV of 18.7%, and NPV of 97.1%. Overall diagnostic accuracy in PAS was 55.9%.Conclusions:The sFlt-1/PlGF ratio effectively predicts preeclampsia but has limited value in PAS, which requires clinical and imaging-based diagnosis.Funding: None.Affiliations- Department of Obstetrics and Gynaecology, Dayanand Medical College & Hospital, Ludhiana