Municipality-Level Availability of IUI and IVF Providers in the Republic of Korea: Spatial Inequality and Autocorrelation

The geographical presence of infertility treatment providers does not by itself establish access or utilization. This cross-sectional ecological study compared December 2025 provider inventories for intrauterine insemination (IUI) and in vitro fertilization (IVF) across 252 harmonized second-level analytical units in the Republic of Korea. The IUI and IVF files contained 264 and 154 geocoded sites, respectively; all IVF-listed sites also appeared in the IUI inventory. Provider density was calculated per 100,000 women aged 20–45 years. Distributional inequality was summarized with Gini and Theil indices. Global and Local Moran statistics used row-standardized Queen weights, 99,999 permutations, and Benjamini–Hochberg false-discovery-rate correction for local tests. IUI and IVF providers were absent from 141 (56.0%) and 176 (69.8%) units. Equal-municipality Gini coefficients were 0.7153 for IUI and 0.8067 for IVF. Raw-density Global Moran’s I was 0.0723 for IUI (p = 0.0791) and 0.0366 for IVF (p = 0.2833). Thirteen IUI local classifications were significant before multiplicity correction, but none remained significant after correction. A two-part sensitivity analysis showed that the binary presence of IUI providers was spatially clustered globally (I = 0.2660, p = 0.0002), whereas raw density was not, indicating that conclusions depend on the indicator used. Raw-density conclusions were stable across alternative age denominators and Queen, Rook, and k-nearest-neighbor specifications. These findings describe provider availability and its spatial distribution, not travel-time accessibility, treatment capacity, or patient use.