Association and diagnostic value of maternal plasma and placental ghrelin levels in predicting early preterm birth: a case–control study

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality worldwide. While inflammation is a known trigger, the role of metabolic-endocrine mediators like ghrelin in the pathogenesis of prematurity remains unclear. This study aimed to evaluate the diagnostic potential of maternal plasma and placental ghrelin levels in predicting early preterm birth and their relationship with systemic inflammatory markers. A total of 60 pregnant women were enrolled and categorized into three groups: Early Preterm (n = 19; < 34 weeks), Late Preterm (n = 17; 34–37 weeks), and Term Control (n = 24; 37–42 weeks). Maternal plasma and placental tissue ghrelin concentrations were quantified using ELISA. Systemic inflammation was assessed via the Neutrophil-to-Lymphocyte Ratio (NLR) and total leukocyte counts. Statistical analysis included ROC curve and univariate logistic regression to determine predictive performance. Both maternal plasma and placental ghrelin levels were significantly higher in the early preterm group compared to late preterm and term cohorts ( p < 0.001). A strong positive correlation was observed between plasma and placental ghrelin concentrations (r = 0.54, p < 0.001). ROC analysis revealed that maternal plasma ghrelin shows high diagnostic performance in this cohort for predicting early PTB, with an Area Under the Curve (AUC) of 0.982 (95% CI: 0.961–1.000) and a cut-off value of > 2797 pg/mL (Sensitivity: 92.0%, Specificity: 100.0%). Univariate logistic regression identified ghrelin as a significant risk factor for early delivery (OR: 1.011, p = 0.014). Notably, no significant correlation was found between ghrelin levels and inflammatory markers (NLR/WBC), suggesting a metabolic signaling pathway independent of generalized systemic inflammation. Elevated maternal plasma and placental ghrelin levels are closely associated with early preterm birth. Given its high diagnostic accuracy and independence from systemic inflammatory markers, maternal ghrelin may serve as a promising predictive biomarker for identifying pregnancies at risk for early spontaneous preterm labor.