Association of municipality-implemented maternal and child health services with infant abuse signs: an ecological study in Japan

<title>Abstract</title> <p>Background In Japan, psychological abuse is the most common form of infant abuse, mostly perpetrated by biological mothers. Early intervention during pregnancy and robust maternal and child health (MCH) services are critical public health strategies for prevention. Although Japan's policy provides an MCH service framework through statutory requirements, implementation relies on mandatory and municipality-specific expansion services. Consequently, delivery varies by municipality, and its impact on abuse risks remains underexplored. We examined relationships among MCH services from pregnancy to postpartum under national policy, abuse signs, and each measure’s preventive role. Methods Aggregated administrative data were collected using a standardized form targeting 1,718 Japanese municipalities (February–June 2024). MCH service performance (process) and infant abuse signs at 3–4 months (outcome) were analyzed using the Donabedian model. From 356 responding municipalities, 238 with data were included. The primary outcome was the absence of abuse signs, while secondary outcomes were physical and psychological abuse signs. Process indicators included home-visiting and screening criteria to identify pregnant/postpartum women requiring support. A negative binomial model with log-link was used; overdispersion was confirmed by likelihood ratio tests (p &lt; 0.05). Incidence rate ratios (IRRs) were also calculated. Results The mean municipal rate for “Absence of abuse signs” was 90.56% ± 11.2%, while the rates for psychological and physical abuse signs were 4.07% ± 2.7% and 0.67% ± 0.7%, respectively. “Postpartum health checkup programs” were significantly associated with the primary outcome (IRR = 1.024, p = 0.012). “Home visits for pregnant women” showed a marginal association without statistical significance (IRR = 1.044, p = 0.074). “Psychological abuse signs” were associated with “Introduction of the public health nurse in charge at MCH Handbook Issuance” (IRR = 1.260, p = 0.022) and “Edinburgh Postnatal Depression Scale screening criteria” (≥ 9 points) (IRR = 0.706, p &lt; 0.01). “Physical abuse signs” were associated with the “Number of public health nurses for MCH” (IRR = 1.070, p = 0.037) and “Support decision criteria for pregnant women requiring support excluding specified expectant mothers” (IRR = 1.235, p = 0.040). Conclusions Municipal MCH service structures—including deployment of public health nurses and identification of pregnant women requiring outreach and support—may assist in infant abuse detection. Enhanced local implementation under national policy frameworks could strengthen the public health infrastructure against infant abuse.</p>