title: Air pollution and stillbirth: a population-based case-control study in Taiwan.
abstract: BACKGROUND
  There is limited evidence suggesting that prenatal exposure to ambient air pollutants may increase the risk of stillbirth, but previous epidemiological studies have not elaborated the most susceptible gestational period for the effects of air pollution exposure on stillbirth.
  
  
  OBJECTIVE
  We estimated associations between exposure to ambient air pollutants and stillbirth, with special reference to the assessment of gestational periods when the fetus is most susceptible.
  
  
  METHODS
  We conducted a population-based case-control study in Taiwan. The case group consisted of 9,325 stillbirths, and the control group included 93,250 births randomly selected from 1,510,064 Taiwanese singleton newborns in 2001-2007. Adjusted logistic regression models were used to estimate odds ratios (ORs) per 10-ppb change for ozone and nitrogen dioxide, 1-ppb change for sulfur dioxide (SO2), 10-μg/m3 change for particulate matter with aerodynamic diameter ≤ 10 μm (PM10), and 100-ppb change for carbon monoxide during different gestational periods and according to term or preterm (< 37 weeks) birth status.
  
  
  RESULTS
  Stillbirth increased in association with a 1-ppb increase in first-trimester SO2 [adjusted OR = 1.02; 95% confidence interval (CI), 1.00-1.04], particularly among preterm births (adjusted OR = 1.04; 95% CI, 1.01-1.07). Stillbirth was also associated with a 10-μg/m3 increase in PM10 during the first (adjusted OR = 1.02; 95% CI, 1.00-1.05) and second (adjusted OR = 1.02; 95% CI, 1.00-1.04) month of gestation, and, as with SO2, associations appeared to be restricted to preterm births (first-trimester adjusted OR = 1.03; 95% CI, 1.00-1.07).
  
  
  CONCLUSIONS
  The study provides evidence that exposure to outdoor air SO2 and PM10 may increase the risk of stillbirth, especially among preterm births, and that the most susceptible time periods for exposure are during the first trimester of gestation.
authors: Department of Occupational Safety and Health, College of Public Health, China Medical University, Taichung, Taiwan. bfhwang@mail.cmu.edu.tw
authors: Bing-Fang
authors: BF
authors: Hwang
authors: Yungling Leo
authors: YL
authors: Lee
authors: Jouni J K
authors: JJ
authors: Jaakkola
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis* / Q000145:classification / Q000633:toxicity*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D018811:Maternal Exposure; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000187:drug effects*; D047928:Premature Birth; D018570:Risk Assessment; D050497:Stillbirth / Q000453:epidemiology*; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000393:Air Pollutants