Maternal exposure to heatwave and preterm birth in Brisbane, Australia

J. Wang, G. Williams, Y. Guo, X. Pan, S. Tong

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Objective To quantify the short-term effects of maternal exposure to heatwave on preterm birth. Design An ecological study. Setting A population-based study in Brisbane, Australia. Population All pregnant women who had a spontaneous singleton live birth in Brisbane between November and March in 2000-2010 were studied. Methods Daily data on pregnancy outcomes, meteorological factors, and ambient air pollutants were obtained. The Cox proportional hazards regression model with time-dependent variables was used to examine the short-term impact of heatwave on preterm birth. A series of cut-off temperatures and durations were used to define heatwave. Multivariable analyses were also performed to adjust for socio-economic factors, demographic factors, meteorological factors, and ambient air pollutants. Main outcome measure Spontaneous preterm births. Results The adjusted hazard ratios (HRs) ranged from 1.13 (95% CI 1.03-1.24) to 2.00 (95% CI 1.37-2.91) by using different heatwave definitions, after controlling for demographic, socio-economic, and meteorological factors, and air pollutants. Conclusions Heatwave was significantly associated with preterm birth: the associations were robust to the definitions of heatwave. The threshold temperatures, instead of duration, could be more likely to influence the evaluation of birth-related heatwaves. The findings of this study may have significant public health implications as climate change progresses.

Original languageEnglish
Pages (from-to)1631-1641
Number of pages11
JournalBJOG: An International Journal of Obstetrics and Gynaecology
Issue number13
Publication statusPublished - Dec 2013
Externally publishedYes


  • Hazards ratio
  • heatwave
  • preterm birth
  • survival analysis

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