Critical Windows of Maternal Exposure to Biothermal Stress and Birth Weight for Gestational Age in Western Australia
Sylvester Dodzi Nyadanu, Gizachew Assefa Tessema, Benjamin J. Mullins, Kevin Chai, Maayan Yitshak‐Sade, Gavin Pereira
Abstract
BACKGROUND: There is limited and inconsistent evidence on the risk of ambient temperature on small for gestational age (SGA) and there are no known related studies for large for gestational age (LGA). In addition, previous studies used temperature rather than a biothermal metric. OBJECTIVES: Our aim was to examine the associations and critical susceptible windows of maternal exposure to a biothermal metric [Universal Thermal Climate Index (UTCI)] and the hazards of SGA and LGA. METHODS: We linked 385,337 singleton term births between 1 January 2000 and 31 December 2015 in Western Australia to daily spatiotemporal UTCI. Distributed lag nonlinear models with Cox regression and multiple models were used to investigate maternal exposure to UTCI from 12 weeks preconception to birth and the adjusted hazard ratios (HRs) of SGA and LGA. RESULTS: years of age, and rural residents were most vulnerable. CONCLUSIONS: Both weekly and monthly specific extreme biothermal stress exposures showed potential critical susceptible windows of SGA and LGA during late gestational periods with disproportionate sociodemographic vulnerabilities. https://doi.org/10.1289/EHP12660.