title: Large social disparities in spontaneous preterm birth rates in transitional Russia.
abstract: OBJECTIVE
  This study estimated the effect of maternal sociodemographic, obstetric and lifestyle factors on the risk of spontaneous preterm birth in a Russian town.
  
  
  METHODS
  All women with singleton pregnancies registered at prenatal care centres in Severodvinsk in 1999 comprised the cohort for this study (n=1559). Analysis was based on spontaneous live singleton births at the maternity home (n=1103). Multivariable logistic regression was applied to quantify the effect of the studied factors on the risk of preterm birth. Differences in gestation duration were studied using multiple linear regression.
  
  
  RESULTS
  In total, 5.6% of all spontaneous births were preterm. Increased risks of preterm delivery were found in women with lower levels of education and in students. Placental complications, stress and a history of fetal death in previous pregnancies were also associated with elevated risks for preterm delivery. Smoking, hypertension and multigravidity were associated with reduced length of pregnancy in metric form.
  
  
  CONCLUSIONS
  In addition to medical risk factors, social factors are important determinants of preterm birth in transitional Russia. Large disparities in preterm birth rates may reflect the level of inequalities in transitional Russia. Social variations in pregnancy outcomes should be monitored.
authors.affiliation: Unit for Preventive Nutrition, Department of Biosciences at Novum, Karolinska Institutet, 141 157 Huddinge, Sweden. Andrej.Grjibovski@TREVNUT.ki.se
authors.forename: A M
authors.initials: AM
authors.lastname: Grjibovski
authors.forename: L O
authors.initials: LO
authors.lastname: Bygren
authors.forename: A
authors.initials: A
authors.lastname: Yngve
authors.forename: M
authors.initials: M
authors.lastname: Sjöström
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D047928:Premature Birth / Q000453:epidemiology*; D011295:Prenatal Care; D012307:Risk Factors; D012426:Russia / Q000453:epidemiology; D012923:Social Class; D012959:Socioeconomic Factors; D013997:Time Factors