Background: A few studies have assessed the relationship between exposure to ambient temperatures during pregnancy and the risk of preterm birth (PTB) but little is known about the impact of maternal exposure to a heatwave on the occurrence of PTB. Aims: To examine the relationship between maternal exposure to a heatwave and the risk of PTB in Brisbane, Australia, during 2000-2010. Methods: We obtained the daily data on sociodemographic factors, air pollutants and meteorological factors and stillbirths for Brisbane, Australia, during 2000-2010 from relevant government agencies. Logistic regression model was used to examine the relationship between maternal exposure to a heatwave and the risk of PTB, after adjusting for maternal age, parity, indigenous status and infants' gender, socioeconomic index for area , relative humidity, air pressure and air pollution. Results: There was a statistically significant association between maternal exposure to a heatwave and the risk of PTB. The relative risk for PTB was 1.25 (95% confidence interval (CI): 1.15-1.35), 1.15 (95% CI: 1.07-1.24), and 1.28 (95% CI: 1.18-1.39) for maternal exposure, in the 1st trimester, to a heatwave defined as daily maximum temperatures ＞ the 90th percentile for 2, 3 or 4 days, respectively. However, no apparent association was observed for maternal exposure to a heatwave in the 2nd or 3rd trimester. Similar results were found when we changed the definition of heatwave (e.g., maximum temperatures ＞ the 95th percentile for 2 or more consecutive days). Conclusions: Maternal exposure to a heatwave during early pregnancy is a significant risk for PTB. Further research is necessary to detail the likely important implications of this finding for the improvement of prenatal care.
展开▼
