title: Does ambient air pollutants increase the risk of fetal loss? A case-control study.
abstract: OBJECTIVE
  To examine the associations between the ambient air pollution and early fetal loss.
  
  
  METHODS
  A retrospective case-control study was conducted. 959 fetal losses and 959 normal intrauterine pregnancies within 14 weeks of pregnancy in 15 general or obstetrics and gynecology hospitals were selected into case and control groups, respectively. Data based on hospital records and national pollution monitor station records were collected. Logistic regression model was conducted to examine the associations between 4 ambient air pollutants (SO2, PM10, NO2 and TSP) exposures and fetal loss.
  
  
  RESULTS
  The ratio of fetal loss to termination of pregnancy for heating months (2.28 %) was significantly (P < 0.001) higher than that for the non-heating months (1.77 %). Logistic regression suggested that fetal loss within 14 weeks was associated with higher exposure to SO2 (OR = 19.76, 95 % CI 2.34-166.71) and TSP (OR = 2.04, 95 % CI 1.01-4.13) in the first month of pregnancy.
  
  
  CONCLUSIONS
  Exposure to high levels of SO2 and TSP during the first month of pregnancy was associated with an increased risk of fetal loss in early pregnancy.
authors.affiliation: Department of Gynecology and Obstetrics, Affiliated Hospital of Chinese People's Armed Police Forces Logistics College, 220 Chenglin Road, Tianjin, 300162, People's Republic of China.
authors.forename: Hai Yan
authors.initials: HY
authors.lastname: Hou
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.forename: Xiao Ping
authors.initials: XP
authors.lastname: Zou
authors.forename: Zhen Hua
authors.initials: ZH
authors.lastname: Yang
authors.forename: Tin-Chiu
authors.initials: TC
authors.lastname: Li
authors.forename: Ya Qiong
authors.initials: YQ
authors.lastname: Chen
mesh_terms: D000028:Abortion, Induced / Q000706:statistics & numerical data; D000328:Adult; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity*; D016022:Case-Control Studies; D002681:China; D005260:Female; D005313:Fetal Death / Q000209:etiology*; D005865:Gestational Age; D020073:Gravidity; D006801:Humans; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D012621:Seasons; D013997:Time Factors; D014505:Urban Population
chemical_list: D000393:Air Pollutants