The Correlation Between First‑Trimester Serum Pregnancy-Associated Plasma Protein A (PAPP-A) Concentrations and the Incidence of Gestational Diabetes

Background & Objective: Given the serious complications associated with Gestational Diabetes Mellitus (GDM), early detection is essential. This study aimed to evaluate the accuracy of Pregnancy‐Associated Plasma Protein A (PAPP‐A) measured during the early first trimester in predicting the development of GDM.Materials & Methods: A prospective study was conducted among pregnant women aged 18-35 years at 11-14 weeks of gestation who attended the Women's Clinic of Ali Ibn Abi Taleb Hospital in Zahedan, Iran, in 2023. Exclusion criteria included multiple gestations, intolerance to glucose testing due to nausea, previous GDM, type 1 or type 2 diabetes, a family history of diabetes, history of macrosomia (>4 kg), preeclampsia, eclampsia, stillbirth, fetal anomalies, recurrent pregnancy loss, smoking or substance use, conception via assisted reproductive technologies, and any known underlying medical conditions. Convenience sampling was used. Participants were referred to the reference laboratory at 11-13 weeks to measure PAPP-A levels and again at 24-28 weeks for standard GDM screening. The chi-square test was applied to assess the association between PAPP-A and GDM. Sensitivity, specseficty, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were calculated to evaluate predictive performance.Results: Among the participants, 122(91%) had PAPP A levels above 0.4 MoM, while 12(9%) had levels below 0.4 MoM. A significant association was observed between PAPP-A levels and blood glucose status. The epidemiologic performance indicators of PAPP-A for predicting GDM demonstrated a PPV of 83%, an NPV of 86%, a sensitivity of 37%, and a specificity of 98%.Conclusion: Our findings suggest that first-trimester PAPP-A levels have meaningful predictive value for identifying women at risk of developing GDM, although they do not serve as perfect diagnostic markers.