title: Vigorous leisure activity and pregnancy outcome.
abstract: BACKGROUND
  Preterm birth is the leading cause of perinatal mortality in North America and Europe and a major predictor of neonatal and infant morbidity. Postterm birth is associated with increased infant mortality and morbidity, as well as increased frequency of surgical or induced labor. Because vigorous leisure activity may affect timing of delivery, this study examined association between vigorous leisure activity and birth outcomes.
  
  
  METHODS
  Women (N = 1,699) with a singleton pregnancy were recruited at 24-29 weeks' gestation from prenatal clinics in central North Carolina between 1995 and 1998. The type and duration of any regular vigorous leisure activity was assessed in a telephone interview covering the 3-month period before pregnancy and during the first and second trimesters of pregnancy.
  
  
  RESULTS
  The prevalence of vigorous leisure activity was 22% before pregnancy, 14% during the first trimester, and 8% during the second trimester. Vigorous leisure activity before pregnancy was unrelated to preterm (<37 weeks) as compared with term delivery (37 to <42 weeks). The risk of preterm birth was somewhat reduced with vigorous leisure activity during the first trimester (odds ratio = 0.80; 95% confidence interval = 0.48-1.35) and more so during the second trimester (odds ratio = 0.52; 95% confidence interval = 0.24-1.11). Vigorous leisure activity before pregnancy or during the first or second trimester was not associated with postterm delivery (>/=42 weeks).
  
  
  CONCLUSIONS
  Vigorous leisure activity during the first trimester, and even more so in the second trimester, was associated with a reduced risk of preterm birth. There was no association with postterm birth. To address the etiologic role of activity on pregnancy outcome and to overcome self-selection, a randomized clinical trial would be needed.
authors.affiliation: Department of Epidemiology, School of Public Health, University of North Carolina-Chapel Hill, NC 27514, USA. kelly_evensen@unc.edu
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Evenson
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Siega-Riz
authors.forename: David A
authors.initials: DA
authors.lastname: Savitz
authors.forename: Jenn A
authors.initials: JA
authors.lastname: Leiferman
authors.forename: John M
authors.initials: JM
authors.lastname: Thorp
mesh_terms: D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007899:Leisure Activities; D009657:North Carolina / Q000453:epidemiology; D005082:Physical Exertion; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second