The Inverse Care Law in Action: How Neonatal ICU Expansion Widened Geographic Disparities in Ecuador (2010–2024)

Background: Neonatal mortality remains a critical challenge in middle-income countries despite significant healthcare investments. Ecuador experienced unprecedented health infrastructure expansion (2010–2017), including construction of tertiary hospitals and neonatal intensive care units (NICUs), yet neonatal mortality reduction has shown geographic heterogeneity and temporal deceleration. Objectives: To evaluate the impact of NICU capacity expansion on neonatal mortality in Ecuador (2010–2024), examine the Inverse Care Law hypothesis in resource distribution, quantify access inequity using concentration indices, and determine incremental cost-effectiveness ratios compared to preventive interventions. Methods: We conducted a nationwide ecological study integrating interrupted time-series analysis and cross-sectional equity assessment. Data sources included vital statistics registries (2010–2024), hospital discharge databases (2022–2024), and census-based socioeconomic indicators. Poisson regression models estimated neonatal mortality rate (NMR) trends following major hospital inaugurations. Equity was assessed through Gini coefficients for bed distribution and concentration curves adjusted for Unsatisfied Basic Needs (UBN) indices. Cost-effectiveness analysis calculated incremental cost per disability-adjusted life year (DALY) averted. Descriptive analyses included correlation matrices and log-transformed histograms for skewed distributions. Results: The dataset comprised 671 canton–year observations (2022–2024) with no missing values in core variables. National NMR declined from 10.9 per 1,000 live births in 2010 to 5.4 in 2024 (50.5% reduction), but provincial disparities persisted. Pichincha and Guayas concentrated 68% of NICU beds (6.22 and 3.67 beds per 1,000 births, respectively), while Bolívar, Carchi, and Amazonian provinces lacked functional Level III units. The Gini coefficient for bed distribution was 0.67. Live births by occurrence showed extreme right-skewness, with few cantons concentrating high values. Correlation matrices revealed strong associations between live births (occurrence and residence) and perinatal discharges (r > 0.85), with relevant correlations between infrastructure indicators, suggesting population size/service effects and potential collinearity. Interrupted time-series analysis revealed no immediate step-change in NMR following major hospital inaugurations. Cost-effectiveness analysis estimated $8,182 USD per DALY averted. The concentration index for mortality was −0.18, confirming disproportionate burden in poorer provinces. Conclusions: NICU expansion contributed to neonatal survival improvements but faces structural limitations including geographic maldistribution, saturated referral systems, and unresolved social determinants. The ecological nature of canton-level data reveals territorial concentration patterns but precludes individual-level causal inference. Achieving further mortality reduction requires transitioning from hospital-centric models to integrated health networks emphasizing regionalized intermediate care, neonatal transport systems, and upstream preventive interventions targeting prematurity and perinatal complications.