title: Maternal physical activity in pregnancy and infant size for gestational age.
abstract: OBJECTIVE
  To estimate the effect of several types of maternal physical activity in pregnancy on size for gestational age and length of gestation.
  
  
  METHODS
  Telephone interviews, birth certificates, and medical records provided data on physical activity and other factors for a random sample of 291 Colorado residents. Backward polychotomous logistic regression modeling yielded estimates of the odds ratios for size for gestational age (appropriate versus small or large) and length of gestation (term versus pre-term or post-term) in relation to second and third trimester maternal physical activity.
  
  
  RESULTS
  Performance of any moderate or vigorous physical activity for two hours per week or more in any month was associated with a decreased risk of large infant size for gestational age (LGA; odds ratio = 0.3, 95% confidence interval = 0.2, 0.7), but had no significant effect on risk of small infant size for gestational age (SGA; odds ratio (OR) = 0.8, 95% confidence interval (CI) = 0.3, 2.3). Length of gestation was not affected by prenatal physical activity.
  
  
  CONCLUSIONS
  These results suggest that prenatal physical activity may decrease risk of LGA, as might be expected given its salutary effects on glucose tolerance.
authors.affiliation: Department of Epidemiology, University of Washington, Seattle 98195-7236, USA.
authors.forename: B W
authors.initials: BW
authors.lastname: Alderman
authors.forename: H
authors.initials: H
authors.lastname: Zhao
authors.forename: V L
authors.initials: VL
authors.lastname: Holt
authors.forename: D H
authors.initials: DH
authors.lastname: Watts
authors.forename: S A
authors.initials: SA
authors.lastname: Beresford
mesh_terms: D001724:Birth Weight; D001827:Body Height; D015986:Confounding Factors, Epidemiologic; D015444:Exercise / Q000502:physiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016017:Odds Ratio; D011247:Pregnancy / Q000502:physiology*; D011256:Pregnancy Outcome; D012189:Retrospective Studies