Prognostic nutritional index as a predictor of fetal growth restriction and adverse perinatal outcomes.

BACKGROUND: Fetal growth restriction (FGR) is a major cause of perinatal morbidity and mortality. Maternal nutritional and inflammatory status may play a role in its development. The Prognostic Nutritional Index (PNI), derived from serum albumin and lymphocyte count, reflects these pathways. AIMS: To investigate the association between maternal PNI and FGR and evaluate the predictive performance of first- and third-trimester PNI for FGR and adverse perinatal outcomes. METHODS: This retrospective study included 279 singleton pregnancies (151 FGR and 128 controls). FGR was defined as estimated fetal weight below the 3rd percentile. First- and third-trimester PNI values were calculated. Logistic regression identified independent predictors of FGR, and receiver operating characteristic analysis assessed predictive performance. RESULTS: First- and third-trimester PNI values were significantly lower in the FGR group than in controls (40.10 vs. 44.07, p<0.001; 37.09 vs. 38.36, p=0.002, respectively). Both first-trimester PNI (adjusted OR 0.80, 95% CI 0.73-0.87, p<0.001) and third-trimester PNI (adjusted OR 0.89, 95% CI 0.79-0.99, p=0.034) were independently associated with FGR. First-trimester PNI showed good predictive performance (AUC 0.76, 95% CI 0.70-0.81), with an optimal cut-off of ≤42.10 (70.9% sensitivity and 72.0% specificity), whereas third-trimester PNI showed lower accuracy (AUC 0.64, 95% CI 0.57-0.71). Lower third-trimester PNI was independently associated with preterm delivery among pregnancies complicated by FGR. CONCLUSIONS: Maternal PNI, particularly in the first trimester, was independently associated with FGR and may serve as a simple biomarker for early risk assessment.