Maternal Serum Concentration of IL-22 in Pregnancy Complicated by Preterm Premature Rupture of Membrane

Abstract

 Intra-amniotic inflammation is a major contributor to preterm labor and premature birth. While few studies have explored the role of maternal serum interleukin-22 (IL-22) in preterm premature rupture of membranes (PPROM), its precise value in diagnosis and prediction remains unclear. This study aimed to evaluate maternal serum IL-22 levels in women with PPROM compared to those with intact membranes and to assess their association with pregnancy outcomes. This case-control study was conducted at Al-Diwaniyah Maternity and Pediatric Teaching Hospital, Iraq, from February to December 2024. It included 60 pregnant women (24–34 weeks of gestation): 30 with PPROM and 30 healthy pregnant controls with intact membranes. Positive C-reactive protein (CRP) was more frequent in the PPROM group (30.0% vs 16.7%), but the difference was not statistically significant (p=0.222). Maternal serum IL-22 levels were significantly higher in the PPROM group (p<0.001). At a cutoff value >200 pg/ml, IL-22 demonstrated excellent diagnostic performance with 96.7% sensitivity, 96.7% specificity, 96.7% positive predictive value, 96.7% negative predictive value, and 96.7% accuracy. The rate of clinical chorioamnionitis was significantly higher in the PPROM group (p=0.002). APGAR scores at 1 and 5 minutes were significantly lower in the PPROM group (p<0.001). The study concluded that Maternal serum IL-22 is a highly accurate biomarker for confirming PPROM. While CRP showed limited predictive value, PPROM remains a significant risk factor for chorioamnionitis and adverse neonatal outcomes. WBC and platelet counts may serve as additional supportive markers.