The impact of physical demands and work hours on the risk of preterm birth among black women.

Kizza, Florence N; Gartner, Danielle R; Liang, Xiaoyu; Harduar Morano, Laurel; Johnson, Candice Y; Misra, Dawn P · J Occup Environ Med · 2026

cross_sectional · Level IV

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Abstract

We investigated the impact of work hours and occupational physical demands on preterm birth (PTB) and explored potential effect modifiers of these associations. 429 Black women employed during pregnancy self-reported hours worked per week. The Karasek Job Content Questionnaire assessed prenatal occupational physical demands. Log binomial regression models were used to estimate associations, adjust for potential confounders, and investigate effect measure modification by psychosocial factors and racism. Prolonged work hours (>40 hours/week) (aPR = 1.83; 95% CI: 0.85, 3.94) and heavy lifting (aPR = 1.33; 95% CI: 0.88, 2.00) were associated with increased PTB prevalence, but awkward body positions were inversely associated with PTB. Social support modified the physical demands and PTB association. Both occupational exposures and non-occupational factors, such as social support, may be important in the etiology of PTB.