title: Maternal exposure to heatwave and preterm birth in Brisbane, Australia.
abstract: OBJECTIVE
  To quantify the short-term effects of maternal exposure to heatwave on preterm birth.
  
  
  METHODS
  An ecological study.
  
  
  METHODS
  A population-based study in Brisbane, Australia.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
authors.affiliation: School of Public Health and Social Work, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: G
authors.initials: G
authors.lastname: Williams
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.forename: X
authors.initials: X
authors.lastname: Pan
authors.forename: S
authors.initials: S
authors.lastname: Tong
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000032:analysis; D001315:Australia / Q000453:epidemiology; D055874:Extreme Heat / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D015999:Multivariate Analysis; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D016016:Proportional Hazards Models; D055815:Young Adult
chemical_list: D000393:Air Pollutants
keywords: Hazards ratio; heatwave; preterm birth; survival analysis