Ambient biothermal stress, preconceptional thyrotropin abnormalities, and the risk of preterm birth: a nationwide Chinese cohort study.

ABSTRACT: Epidemiologic evidence on thermal stress and preterm birth (PTB) is based on ambient temperature rather than a biothermal metric. Thyrotropin abnormalities have been associated with PTB and may increase thermal vulnerability. However, it remains unknown whether thermal stress and thyrotropin abnormalities synergistically contribute to increased risk of PTB. Here we conducted a nationwide cohort study among 6,218,131 singleton live births in China. Biothermal stress was measured using the Universal Thermal Climate Index. We found that both heat stress and cold stress during each trimester were associated with increased risks of PTB, with hazard ratios ranging from 1.06 (95% confidence interval [CI]: 1.05, 1.07) to 2.33 (95% CI: 2.30, 2.35) and from 1.08 (95% CI: 1.07, 1.09) to 1.68 (95% CI:

SUBMITTER: He X 

PROVIDER: S-EPMC12550002 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature