Preterm delivery and exposure to active and passive smoking during pregnancy: a case-control study from Italy

Paediatr Perinat Epidemiol. 2007 May;21(3):194-200. doi: 10.1111/j.1365-3016.2007.00815.x.


The aim of this study was to assess the relationship between preterm/early preterm delivery and active smoking as well as environmental tobacco smoke (ETS) exposure in a sample of pregnant Italian women. A case-control study was conducted in nine cities in Italy between October 1999 and September 2000. Cases of preterm birth were singleton babies born before the 37th gestational week; babies born before the 35th gestational week were considered early preterm births. Controls were babies with gestational ages >or= 37th week. A total of 299 preterm cases (including 105 early preterm) and 855 controls were analysed. A self-administered questionnaire was used to assess active smoking and ETS exposure, as well as potential confounders. Multivariable logistic regression analysis showed a relationship between active smoking during pregnancy and preterm/early preterm delivery [adjusted ORs: 1.53; 95% CI 1.05, 2.21 and 2.00; 95% CI 1.16, 3.45, respectively]. A dose-response relationship was found for the number of cigarettes smoked daily. The adjusted ORs were 1.54 and 1.69 for preterm babies and 1.90 and 2.46 for early preterm babies for 1-10 and >10 cigarettes/day respectively. ETS exposure was associated with early preterm delivery [adjusted OR 1.56; 95% CI 0.99, 2.46] with a dose-response relationship with the number of smokers in the home. Smoking during pregnancy was strongly associated with preterm delivery with a dose-response effect. ETS exposure in non-smoking women was associated only with early preterm delivery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Case-Control Studies
  • Female
  • Humans
  • Infant, Newborn
  • Italy / epidemiology
  • Male
  • Maternal Exposure / adverse effects*
  • Maternal Exposure / statistics & numerical data
  • Pregnancy
  • Premature Birth / epidemiology
  • Premature Birth / etiology*
  • Prevalence
  • Risk Factors
  • Smoking / adverse effects*
  • Smoking / epidemiology
  • Tobacco Smoke Pollution / adverse effects*
  • Tobacco Smoke Pollution / statistics & numerical data


  • Tobacco Smoke Pollution