Study on indoor thermal perception, behavioral adaptation in late pregnancy and their effects on adverse birth outcomes in south China

Abstract

Pregnant women are vulnerable to environmental heat exposure. However, little is known about their thermal perception and adaptation, and the relationship with birth outcomes. We conducted a prospective study involving 1680 pregnant women admitted to the hospital for delivery during the summer months in South China. The demographic characteristics, indoor thermal perception (thermal sensation, comfort, preference, acceptability, and tolerance), and behavioral adaptations (i.e., regulation of behavior to achieve thermal comfort) for the month preceding the survey were collected. By following them up to delivery, birth outcomes were collected including gestational age and birth weight. We assessed the association between indoor environment and thermal perception, and identified acceptable temperature range (ATR). Structural equation model was employed to assess the association between thermal perception, behavioral adaptation, and adverse birth outcomes. A large proportion expressed discomfort with the environment (87.1 %) and found it intolerable (30.1 %). The upper limit of the ATR for the surveyed pregnant women was determined to be 24.4 °C. Higher ambient temperature, relative humidity, maternal age, and prenatal BMI were found associated with an increased level of thermal perception (β = 0.093, P < 0.01; β = 0.314, P < 0.001; β = 0.061, P < 0.05; β = 0.060, P < 0.05, respectively). This, in turn, influenced the use of air conditioning (β = 0.129, P < 0.001), which were associated with reduced risk of small for gestational age (β = −0.081, P < 0.05). The results will guide individualized thermal adaptation and optimize thermal environment for pregnant women.