Abstract: Objective To explore the expression of inducible nitric oxide synthase (iNOS) and mammalian target of rapamycin complex 1 (mTORC1) in premature rupture of membranes (PROM) complicated by chorioamnionitis (CA) and its correlation with macrophage polarization, in order to provide evidence for early clinical diagnosis and intervention. Methods A total of 100 pregnant women with PROM who underwent cesarean section at the Affiliated Hospital of Xuzhou Medical University from October 2022 to October 2023 were selected as a study group. According to the time of membrane rupture, they were divided into two subgroups (n=50): a term PROM (TPROM) group and a preterm PROM (PPROM) group. Based on the presence of CA, both groups were further subdivided into four groups: a PROM with chorioamnionitis (TPROM-CA+) group, a preterm PROM with chorioamnionitis (PPROM-CA+) group, a term PROM without chorioamnionitis (TPROM-CA-) group, and a preterm PROM without chorioamnionitis (PPROM-CA-) group. Meanwhile, 30 pregnant women with normal full-term pregnancies who delivered via cesarean section was included in a control group. The levels of serum mTORC1 were measured by ELISA. All membrane samples were pathologically examined, and the expression of iNOS and mTORC1 in the membrane tissues was assessed by immunohistochemistry. Results The incidence of CA was 42% (21/50) in the TPROM group, 56% (28/50) in the PPROM group, and 0 (0/30) in the control group, with statistical differences among the three groups (P<0.05). The levels of serum mTORC1 in the TPROM-CA+ and PPROM-CA+ groups were significantly higher than the other three groups (P<0.05), but no statistical difference was found between the TPROM-CA+ and PPROM-CA+ groups (P>0.05). ROC curve analysis indicated that the expression of serum mTORC1 in PROM pregnant women has diagnostic value for CA in PROM patients. Immunohistochemical results showed that the levels of iNOS and mTORC1 in the membrane tissues of the TPROM-CA+ and PPROM-CA+ groups were significantly higher than the other three groups (P<0.05). There was no statistical difference in the expression of the two factors between the TPROM-CA+ and PPROM-CA+ groups (P>0.05). Furthermore, iNOS expression in CA stage I was higher than those in stages II and III, while mTORC1 expression showed the opposite trend, with statistical differences (P<0.05). Conclusions Elevated serum mTORC1 levels may have predictive value for PROM complicated by CA. The upregulation of iNOS and mTORC1 in PROM complicated by CA suggests that iNOS and mTORC1 may be involved in the development of CA by inducing macrophage polarization.