title: Air pollution exposure in early pregnancy and adverse pregnancy outcomes: a register-based cohort study.
abstract: OBJECTIVE
  Our aim was to study the possible associations between exposure to elevated levels of air pollution, ozone (O(3)) and vehicle exhaust (NO(x)), during early gestation, and adverse pregnancy outcomes such as pre-eclampsia, preterm birth and small for gestational age.
  
  
  METHODS
  Prospective register-based cohort study.
  
  
  METHODS
  The Swedish Medical Birth Register includes data on all deliveries during 1998 to 2006 in Greater Stockholm, Sweden. The national Patient Register and the Prescribed Drug Register were used to collect information on maternal asthma.
  
  
  METHODS
  All singleton pregnancies, conceived at the earliest in August 1997 and at the latest in February 2006, were included, n=120 755.
  
  
  METHODS
  We studied preterm birth, small for gestational age and pre-eclampsia.
  
  
  RESULTS
  4.4% of pregnancies resulted in a preterm birth. The prevalence of pre-eclampsia was 2.7%. We observed an association between first trimester O(3) and preterm birth (OR 1.04, 95% CI 1.01 to 1.08) as well as an association with pre-eclampsia (OR 1.04, 95% CI 1.01 to 1.08), per 10 µg/m(3) increase in O(3). We observed no association between first trimester NO(x) and adverse pregnancy outcomes. No associations were observed between any of the air pollutants and small for gestational age.
  
  
  CONCLUSIONS
  Increased levels of O(3) during the first trimester increased the risk of pre-eclampsia and preterm birth. Air pollutants did not exhibit any effects on fetal growth restriction. We estimated 1 in every 20 cases of pre-eclampsia to be associated with O(3) exposure.
authors: Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine,  Umeå University, Umeå,  Sweden.
authors: David
authors: D
authors: Olsson
authors: Ingrid
authors: I
authors: Mogren
authors: Bertil
authors: B
authors: Forsberg
references: Int J Environ Res Public Health. 2012 Jan;9(1):272-85
references: 22470291
references: Environ Health Perspect. 2006 Nov;114(11):1636-42
references: 17107846
references: Environ Health Perspect. 2008 May;116(5):680-6
references: 18470315
references: Birth Defects Res C Embryo Today. 2004 Dec;72(4):300-12
references: 15662709
references: Hypertension. 2011 Mar;57(3):406-12
references: 21220700
references: Environ Health Perspect. 2005 Sep;113(9):1212-21
references: 16140630
references: Epidemiology. 2000 Sep;11(5):502-11
references: 10955401
references: Environ Res. 2011 Jul;111(5):685-92
references: 21453913
references: BJOG. 2011 Oct;118(11):1314-23
references: 21749633
references: Pediatrics. 2007 Jul;120(1):70-7
references: 17606563
references: Environ Res. 2010 Nov;110(8):778-85
references: 20932516
references: Biol Neonate. 2002;81(3):146-57
references: 11937719
references: Am J Obstet Gynecol. 2007 Sep;197(3):239.e1-5
references: 17826403
references: Kidney Int. 2009 Oct;76(8):831-7
references: 19657323
references: J Epidemiol Community Health. 2009 Jun;63(6):488-96
references: 19359274
references: Environ Health Perspect. 2000 Feb;108(2):173-6
references: 10656859
references: Environ Res. 2011 Jan;111(1):125-35
references: 21067713
references: Environ Health Perspect. 2001 Aug;109 Suppl 4:523-7
references: 11544157
references: Vasc Health Risk Manag. 2011;7:467-74
references: 21822394
references: BJOG. 2006 Aug;113(8):935-41
references: 16907939
references: Environ Health Perspect. 2005 May;113(5):602-6
references: 15866770
references: Int Arch Occup Environ Health. 2009 Apr;82(5):613-21
references: 18998152
references: Pediatrics. 2011 Jun;127(6):1052-9
references: 21555500
references: Environ Health. 2007 Jun 07;6:16
references: 17553174
references: Environ Health Perspect. 2003 Nov;111(14):1773-8
references: 14594630
references: Environ Health. 2010 Jan 29;9:6
references: 20113501
references: Hypertension. 2010 May;55(5):1254-9
references: 20231527
references: J Thromb Haemost. 2009 Mar;7(3):375-84
references: 19087223
references: Paediatr Perinat Epidemiol. 2006 Nov;20(6):454-61
references: 17052280
references: Epidemiology. 2009 Sep;20(5):689-98
references: 19478670
references: Am J Epidemiol. 2007 Nov 1;166(9):1045-52
references: 17675655
references: Environ Res. 2008 Feb;106(2):185-94
references: 18021762
references: Ultrasound Obstet Gynecol. 2000 Jan;15(1):36-40
references: 10776010
references: Environ Health Perspect. 2011 Apr;119(4):553-8
references: 21212043
references: Environ Health Perspect. 2006 Jun;114(6):905-10
references: 16759993
references: Pediatrics. 2010 Jan;125(1):e67-73
references: 19969613
references: Matern Child Health J. 2013 Apr;17(3):545-55
references: 22544506
references: Biomed Environ Sci. 2007 Oct;20(5):426-31
references: 18188997