Dynamic analysis of critical maternal complications in tertiary hospitals in Wuxi: A study based on four years of monitoring data

Background Severe maternal morbidity (SMM) is a significant public health concern. This study analyzed the incidence, trends, causes, and pregnancy outcomes of SMM in Wuxi to inform future clinical and public health strategies. Methods A retrospective analysis was conducted on 315 critical maternal cases identified from 156,435 deliveries in Wuxi between October 1, 2020, and September 30, 2024. Data were extracted from a citywide near-miss maternal surveillance system. Statistical analyses were performed using SPSS 25.0, employing chi-square tests and Cochran-Armitage trend tests to evaluate trends, and chi-square tests for comparisons between groups. Results The overall incidence of SMM was 0.20%. Initially, this rate remained stable at 0.19% across the first three cycles (P > 0.05); however, it significantly increased to 0.24% during the cycle from October 2023 to September 2024 (χ² = 5.24, P = 0.02). This increase was closely associated with a rise in the proportion of women of advanced maternal age (≥35 years), which reached 26.03% (χ² = 11.76, P = 0.001). Over time, the distribution of risk levels shifted. Initially, the high-risk group was dominant (63.29%), but in recent cycles, the moderate-risk group became more prominent (64.44%). The moderate-risk group was associated with a higher rate of adverse outcomes (25.00–25.71%) compared to the high-risk group (17.11–20.69%; χ² = 10.83, P = 0.01). Direct obstetric factors were the primary causes, accounting for 79.05% of cases, with obstetric hemorrhage being the most prevalent (53.97%). In contrast, the proportion of cases attributable to indirect obstetric factors increased from 17.81% to 26.67%, primarily due to heart disease and infectious diseases. Conclusion Improving maternal safety involves dynamic risk assessments, tiered referrals for moderate-risk pregnancies, better multidisciplinary management of complications, optimized emergency responses in primary care, and refined regional referral systems to reduce preventable SMM and mortality.