title: Effect of psychosocial stress and physical activity on low birthweight: a cohort study.
abstract: OBJECTIVE
  To determine the effect of physical activity and psychosocial stress on low birthweight (LBW).
  
  
  METHODS
  A prospective study was carried out in a district of Sri Lanka between May 2001 and April 2002. A total of 885 pregnant mothers were recruited at < or = 16 weeks of gestation and followed up until partus. Trimester-specific exposure statuses along with potential confounding factors were gathered on average at the 12th, 28th, and 36th weeks of gestation. Physical activities were assessed by inquiring about the duration of specific postures adopted per day by housewives during each trimester at home and both at home and during working hours for those who were engaged in paid employment. Psychosocial stress was assessed using the Modified Life Events Inventory and the General Health Questionnaire 30. LBW was defined as a birthweight of less than 2500 g. Multiple logistic regression analysis was applied for controlling confounders and the results were expressed as adjusted odds ratios (OR) and 95% confidence intervals (95%CI).
  
  
  RESULTS
  Standing > 2.5 h/day (OR 2.26; 95%CI 1.10, 4.69) during the second trimester and sleeping 8 h or less/day (OR 2.84; 95%CI 1.49, 5.40) either during the second, third or both trimesters together, an increase in maternal age in years (OR 0.92; 95%CI 0.87, 0.98), and body mass index < 19.8 kg/m(2) (OR 2.2; 95%CI 1.17, 4.22) had a statistically significant association with LBW. Psychosocial stress was not associated with LBW.
  
  
  CONCLUSIONS
  Standing > 2.5 h/day and sleeping < or = 8 h/day were risk factors for LBW, whereas psychosocial stress was not.
authors.affiliation: Department of Public Health, Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka. chrishantha-abeysena@mfac.kln.ac.lk
authors.forename: Chrishantha
authors.initials: C
authors.lastname: Abeysena
authors.forename: Pushpa
authors.initials: P
authors.lastname: Jayawardana
authors.forename: Rohini de A
authors.initials: Rde A
authors.lastname: Seneviratne
mesh_terms: D005260:Female; D005865:Gestational Age; D006304:Health Status; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D009043:Motor Activity / Q000502:physiology*; D016017:Odds Ratio; D011247:Pregnancy; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D012890:Sleep / Q000502:physiology; D012944:Social Support; D013188:Sri Lanka; D013315:Stress, Psychological / Q000150:complications / Q000503:physiopathology*; D011795:Surveys and Questionnaires