Abstract: OBJECTIVE To study the influencing factors for chorionic amnitis infection in women with premature rupture of fetal membrane and the correlation of niacinamide phosphate ribose transferase (NAMPT), serum β-chorionic gonadotropin (β-HCG) and secreted frizzy-associated protein 5 (SFRP5) with the infection. METHODS Total of 40 women with premature rupture of membranes complicated with chorioamnitis infection admitted to Zhoushan Women and Children's Hospital from Jan 2019 to Dec 2022 were recruited as the chorioamnitis group, and 64 women with premature rupture of membranes without chorioamnitis infection admitted to the hospital during the same period were selected as the non-chorioamnitis group. The risk factors of chorioamnitis infection in women with premature rupture of fetal membrane were analyzed by univariate and multivariate logistic regression analysis. The expression levels of NAMPT in fetal membrane tissue and serum β-HCG and SFRP5 were compared between the two groups. The predictive value of NAMPT in fetal membrane tissue, serum β-HCG and SFRP5 in women with premature rupture of fetal membrane and chorioamnitis was analyzed by receiver operating characteristic (ROC) curve. RESULTS Multivariate logistic regression analysis showed that pregnant women with premature rupture of membranes <32 weeks, rupture of membranes ≥48 h, oligohyniotic fluid were independent risk factors for chorionic amnitis infection (P＜0.05). The levels of NAMPT in fetal membrane tissue and serum β-HCG and SFRP5 of chorionic amniotic infection group were higher than those of non-chorionic amniotic infection group, while the levels of serum SFRP5 was lower than those of non-chorionic amniotic infection group (P＜0.05). The area under the curve (AUC) and specificity of NAMPT combined with serum β-HCG and SFRP5 detection in the fetal membrane tissues were higher than those of the three tests alone (P＜0.05). CONCLUSION There are many independent risk factors for chorioamniotic infection in women with premature rupture of membranes, and the combination of NAMPT and serum β-HCG and SFRP5 is a good predictor of chorioamniotic infection in women with premature rupture of membranes.