Diagnostic Value of Maternal Zonulin Levels in Fetal Growth Disorders

Zonulin, a biomarker linked to intestinal barrier dysfunction, may contribute to fetal growth disorders such as intrauterine growth restriction (IUGR) and small-for-gestational-age (SGA) pregnancies. This study evaluated maternal serum zonulin levels as a diagnostic tool for distinguishing IUGR from SGA and investigated their associations with perinatal outcomes.

This cross-sectional study included singleton pregnancies between 32 and 37 weeks. Maternal blood samples collected at 16-18 weeks of gestation were analyzed for serum zonulin levels using ELISA, with measurements performed after group classification based on the final diagnosis (IUGR, SGA, and appropriate-for-gestational-age [AGA]). Demographic, obstetric, and neonatal data were analyzed. Diagnostic performance was assessed via receiver operating characteristic (ROC) curve analysis.

Maternal serum zonulin levels were highest in the IUGR group, followed by SGA and AGA (p<0.001). The optimal cutoff for diagnosing IUGR was 15.70 ng/mL, with a sensitivity of 86.7% and specificity of 62.5% (AUC: 0.779). For distinguishing IUGR from SGA, the cutoff was 20.28 ng/mL (sensitivity: 71.7%, specificity: 73.3%, AUC: 0.748). Zonulin levels negatively correlated with birth weight, gestational age, and Apgar scores (p< 0.05).

Maternal serum zonulin shows significant diagnostic potential for identifying IUGR and distinguishing it from SGA pregnancies. These findings suggest that zonulin could serve as a biomarker for pathological fetal growth restriction, warranting further studies to confirm its clinical utility.