Geospatial analysis of area-level social and behavioral factors associated with short interpregnancy intervals in North Carolina, U.S.

Abstract

Objective

Short interpregnancy intervals (sIPI), defined as six months or less, are associated with adverse birth outcomes and are influenced by socioeconomic factors, which reflect a complex interplay between health outcomes, social factors, health behaviors, and geographic contexts. This study aims to examine the spatial distribution of sIPI across North Carolina, in the Southeast United States (U.S.), and assess its association with social and behavioral factors.

Methods

We used secondary data from the North Carolina State Center for Health Statistics and the U.S. Census Bureau spanning 2018–2022 to analyze the spatial distribution of sIPI. Associations between sIPI and social and behavioral factors—including race, fertility age, educational attainment, poverty rates, transportation, prenatal smoking, prenatal care in the first trimester, and breastfeeding initiation rates—were assessed using ordinary least squares and spatial lag models.

Results

County-level analyses revealed significant spatial autocorrelation of sIPI in North Carolina. Mecklenburg County had the highest number of cases (n = 6255), while Jones County had the highest percentage (18.9 %). No significant urban–rural differences were found. High-high clusters were primarily located in western Mountain and southern Coastal counties. SIPI was positively associated with the percentage of reproductive-age females and limited vehicle access, with a significant spatial lag term indicating spatial dependence.

Conclusions

Findings emphasize the need for targeted public health interventions such as comprehensive school-based sexual health education and group-level prenatal care programs to reduce the prevalence of sIPI, prevent subsequent adverse birth outcomes, and mitigate geographic health disparities in North Carolina, U.S.