关键词: 妊娠期, 高温热浪暴露, 早产, 健康防护行为, 中介效应

Abstract: Objective To investigate the mediating effect of maternal health protective behaviors on the association between heatwave exposure during pregnancy and preterm birth, thereby providing a theoretical foundation for health education interventions aimed at mitigating heat-related risks during gestation. Methods A convenience sampling method was employed to recruit 583 pregnant women who underwent inpatient delivery at Wuhan First Hospital between July and September 2025. Data were collected utilizing a self-administered maternal heatwave-health protective behavior questionnaire alongside a general demographic survey. Maternal exposure to heatwaves during pregnancy was determined by integrating survey data with meteorological records from local monitoring stations. A mediation model was subsequently constructed to analyze the mediating role of health protective behaviors in the relationship between heatwave exposure and preterm birth. Results Of the 583 eligible participants, 576 completed the investigation. Preterm birth was recorded in 30 cases (5.21%), and heatwave exposure was identified in 190 cases (32.99%). The mean score for health protective behaviors was (56.66±6.18). The preterm birth cohort exhibited a significantly higher incidence of heatwave exposure and significantly lower health protective behavior scores compared to the full-term cohort (P<0.05). Statistically significant differences were also observed in both health protective behavior scores and the incidence of preterm birth across different maternal age groups and educational attainment levels (P<0.05). Point-biserial correlation analysis revealed that heatwave exposure was positively correlated with preterm birth (r=0.101, P=0.015) and negatively correlated with health protective behavior scores (r=-0.100, P=0.017). Furthermore, health protective behavior scores were negatively associated with preterm birth (r=-0.435, P<0.001). Bootstrap mediation analysis demonstrated that heatwave exposure exerted a direct positive effect on preterm birth (B=0.849, P=0.034) and a negative effect on health protective behavior scores (β=-0.180, P=0.017); conversely, health protective behavior scores exerted a negative effect on preterm birth (B=-0.453, P<0.001). Health protective behaviors functioned as a partial mediator in the association between heatwave exposure and preterm birth, with the indirect effect accounting for 38.85% of the total effect. Conclusion Heatwave exposure during pregnancy exerts a direct deleterious effect on the incidence of preterm birth, while additionally manifesting an indirect effect mediated through maternal health protective behaviors.

Key words: Pregnancy, Heatwave exposure, Preterm birth, Health protective behaviors, Mediating effect