Theory of planned behavior constructs and self-reported thyroid health-preventive behaviors among women of reproductive age in Khuzestan Iran

Congenital hypothyroidism (CH) is the most common congenital endocrine disorder and one of the preventable causes of intellectual disability through timely diagnosis and treatment. Understanding thyroid health-preventive behaviors during the reproductive years may provide useful insights for health promotion. This study aimed to assess thyroid health–preventive behaviors and their associated beliefs among reproductive-aged women in Khuzestan Province, Iran, based on the Theory of Planned Behavior (TPB). This cross-sectional study included 411 women of reproductive age selected through multistage random sampling between May 2023 and February 2024. Data were collected using a self-designed questionnaire with established validity and reliability, covering sociodemographic characteristics, knowledge, and TPB constructs. The outcome was self-reported thyroid health–preventive behavior, categorized as optimal or non-optimal adherence. Data were analyzed using the Kruskal–Wallis test, Mann–Whitney U test, correlation analysis, and univariate and multivariable logistic regression. In the multivariable logistic regression analysis of 411 participants, higher intention (adjusted OR = 1.16, 95% CI: 1.01–1.35), subjective norm (adjusted OR = 1.12, 95% CI: 1.05–1.20), perceived behavioral control (adjusted OR = 1.20, 95% CI: 1.07–1.34), and attitude (adjusted OR = 1.14, 95% CI: 1.06–1.23) were associated with higher odds of optimal adherence to thyroid health–preventive behaviors (all p < 0.05). Knowledge was significantly associated with preventive behaviors in the unadjusted analysis, but the association was attenuated and was no longer statistically significant after adjustment (adjusted OR = 0.95, 95% CI: 0.87–1.03, p = 0.203). This study found associations between TPB constructs and self-reported thyroid health–preventive behaviors among women of reproductive age. Attitudes, Subjective norm, perceived behavioral control, and intention may be relevant to preventive practices. These findings may inform the development of tailored educational and health promotion strategies that could be considered within existing preconception, antenatal, and postnatal healthcare services. Further longitudinal and intervention research is needed to determine whether such strategies are associated with sustained changes in preventive behaviors.