title: Paternal and maternal smoking habits before conception and during the first trimester: relation to spontaneous abortion.
abstract: OBJECTIVE
  This study examined the association between maternal smoking before and during the first trimester of pregnancy and spontaneous abortion.
  
  
  METHODS
  We have been conducting a hospital-based case-control study on risk factors for spontaneous abortion in the greater Milan area. We collected information from 782 cases of spontaneous abortions and 1543 controls (women who delivered at term healthy infants).
  
  
  RESULTS
  With respect to never smokers, the odds ratio (OR) were 0.7 (95%, confidence interval (CI), 0.5-1.0) for women who quit smoking and 1.3 (95% CI, 1.0-1.6) for those who continued during pregnancy. Women who smoked more than 10 cigarettes/day in the first trimester were at increased risk of miscarriage, with an OR of 1.4 (95% CI, 1.0-2.1). No relationship was evident between the number of cigarettes smoked before conception and the risk of abortion. Likewise, no association emerged between paternal smoking and miscarriage. Moreover, no significant interaction or modification effect was obtained when strata of age and other major characteristics were investigated.
  
  
  CONCLUSIONS
  The risk of abortion associated with cigarette smoking during the first trimester of pregnancy was measurable and noticeable in this population, and accounted for 9% (95% CI, 6-13%) of all cases. The increased risk of spontaneous abortion in women smoking during pregnancy is a further reason to encourage pregnant women to quit.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Chatenoud
authors.forename: F
authors.initials: F
authors.lastname: Parazzini
authors.forename: E
authors.initials: E
authors.lastname: di Cintio
authors.forename: G
authors.initials: G
authors.lastname: Zanconato
authors.forename: G
authors.initials: G
authors.lastname: Benzi
authors.forename: R
authors.initials: R
authors.lastname: Bortolus
authors.forename: C
authors.initials: C
authors.lastname: La Vecchia
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology*; D000328:Adult; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D005220:Fathers; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011297:Prenatal Exposure Delayed Effects; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution
chemical_list: D014028:Tobacco Smoke Pollution