Minming Chen ^1,2,3 Wei Feng ^1,2,3 Jinping Hou ^1,2,3 Xiaohong Die ^1,2,3 Zhenhua Guo ^1,2,3 Yi Wang ^1,2,3*

• ¹ National Center for Child Health and Disease Clinical Research (NCRCCH), Hangzhou, China
• ² Children‘s Hospital of Chongqing Medical University, Chongqing, China
• ³ Chongqing Key Laboratory of Pediatrics, Children‘s Hospital of Chongqing Medical University, Chongqing, China

Purpose: This study investigates the clinical characteristics of necrotizing enterocolitis-associated intestinal perforation (NEC-IP) in neonates across various gestational ages (GAs) and identifies risk factors linked to poor prognosis in these patients. Methods: This retrospective study analyzed NEC-IP patients’ basic information, comorbidities, intraoperative findings, treatment protocols, and prognoses. According to the GA, patients were divided into three groups: early (GA: 28 ~<32 weeks, Group 1), mid-term (GA: 32 ~<34 weeks, Group 2), and late (GA: 34 ~<37 weeks, Group 3). The clinical features of the three groups were analyzed, and risk factors for poor prognosis were identified.Results: Of the 113 cases, the number of cases in Groups 1 to 3 was 36 (31.9%), 44 (38.9%), and 33 (29.2%), respectively; and the overall proportion of poor prognosis was 19.4% (22/113). For basic information, the birth weight of Group 1 was lower than that of Group 2 and Group 3, while the postnatal day at the time of surgery of NEC and the onset age were higher than that of Group 2 (P < 0.016). For comorbidity, the incidence of sepsis, coagulopathy, type of (congenital heart disease) CHD, and hypoproteinemia in Group 1 was higher than that in Group 2 (all P < 0.016), and the incidence of respiratory failure, hypoproteinemia in Group 1 was higher than that in Group 3 (all P < 0.016). For related treatment, the usage rate of vasoactive substances and mechanical ventilation in Group 1 was higher than that of Group 2 and Group 3 (all P < 0.016). "Lasso and logistic regression analysis identified GA (OR: 0.274, 95% CI: 0.078–0.796), sepsis (OR: 7.955, 95% CI: 1.424–65.21), coagulopathy (OR: 19.51, 95% CI: 3.393–179.1), CHD (OR: 6.99, 95% CI: 1.418–54.83), and diseased bowel segment (OR: 2.804, 95% CI: 1.301–7.316) as independent risk factors for poor prognosis (all P < 0.05).The clinical features of NEC-IP patients differ based on GA, particularly in terms of CHD type, postnatal day at the time of surgery, utilization of vasoactive substances, and prognosis. Furthermore, GA, sepsis, coagulopathy, CHD, and diseased bowel segment are independent factors for poor prognosis of patients with NEC-IP.