Neonatal mortality as a sentinel indicator for health system performance: a 33-year analysis of China’s maternal and child health policies

Background: This study aims to research short-term disequilibrium adjustments and long-term cointegration relationships among the maternal mortality ratio (MMR), under-five mortality rate (U5MR), infant mortality rate (IMR), and neonatal mortality rate (NMR), while evaluating the contributions of pivotal health policies and service coverage. Methods: Using nationally representative longitudinal data (1991-2023), this study applied Joinpoint regression model to identify trend inflection points and calculate average annual percent change (AAPC), Pearson correlation analysis to assess inter-indicator associations, and vector error correction model framework to analyse cointegration and short-term dynamics after establishing stationarity and causality. Results: = -7.40%), with inflection points aligning with major policy implementations. Strong positive correlations were observed among all indicators (ρ≥0.980). The vector error correction model revealed three cointegrating vectors, confirming long-term equilibrium relationships. The NMR demonstrated faster error correction speed (error-correction term = -0.89, P = 0.030) and was identified as the Granger cause of MMR, U5MR, and IMR (P < 0.05). Policy analyses revealed that New Rural Cooperative Medical Scheme expansion significantly reduced NMR (α = -0.26, P = 0.006), whereas hospital delivery rate exhibited a counterintuitive short-term positive association with NMR (α = 0.05, P = 0.013). The Reducing Maternal Mortality and Eliminating Neonatal Tetanus project significantly reduced IMR (α = -0.25, P = 0.014), outperforming isolated neonatal visits. Conclusions: The NMR serves as a pivotal sentinel indicator for China's maternal and child health system performance, with Granger-causal precedence over other metrics. Phased health policies, particularly New Rural Cooperative Medical Scheme and Reducing Maternal Mortality and Eliminating Neonatal Tetanus project, accelerated mortality reductions through distinct mechanistic pathways, despite short-term trade-offs. These findings provide a transferable policy blueprint for low- and middle-income countries to accelerate progress towards Sustainable Development Goal 3.2 through equity-oriented reforms.