title: Early spontaneous preterm deliveries before 34 weeks' gestation in a tertiary care centre: analysis of maternal factors and obstetric history.
abstract: OBJECTIVE
  The aim of this study is to investigate risk factors associated with spontaneous early preterm delivery.
  
  
  METHODS
  The study included 1865 singleton pregnancies with 31 spontaneous deliveries between 23 and 35 weeks' gestation compared to 1834 deliveries at the term analysed between 2008 and 2009. Both groups were 100% Caucasian.
  
  
  RESULTS
  Spontaneous early delivery occurred in 31(1.2%) of the 2528 pregnancies. In the preterm delivery group, compared with unaffected pregnancies, there was an increased incidence of maternal anaemia (OR 2.8, 95%CI: 1.8-4.5; p < 0.001). Previous preterm delivery between 23 and 34 weeks' gestation (OR 10.7, 95%CI: 5.2-21.7; p < 0.001) as well as vaginal bleeding beyond the first trimester (OR 3.8, 95%CI: 1.2-12.1; p = 0.039), assisted conception (4.1, 95%CI: 2.0-8.4; p = 0.001) and fetal loss before 16 weeks' gestation (OR 4.2, 95%CI: 2.5-7.1; p < 0.001) are strongly associated with spontaneous preterm delivery.
  
  
  CONCLUSIONS
  Previous preterm delivery as well as fetal loss before 16 weeks' gestation, assisted conception, vaginal bleeding beyond the first trimester and maternal anaemia are strongly associated with an increased risk for spontaneous early preterm delivery.
authors.affiliation: Department of Obstetrics, Women' Diseases and Oncogynecology, Central Clinical Hospital of Ministry of Interior, Warsaw, Poland.
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Beta
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Issat
authors.forename: Małgorzata A
authors.initials: MA
authors.lastname: Nowicka
authors.forename: Marta
authors.initials: M
authors.lastname: Andziak
authors.forename: Artur J
authors.initials: AJ
authors.lastname: Jakimiuk
mesh_terms: D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D016015:Logistic Models; D011044:Poland / Q000453:epidemiology; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D017584:Reproductive History; D012189:Retrospective Studies; D062606:Tertiary Care Centers / Q000706:statistics & numerical data