Parental cigarette smoking and the risk of spontaneous abortion

Am J Epidemiol. 1992 Jun 15;135(12):1394-403. doi: 10.1093/oxfordjournals.aje.a116250.


Although cigarette smoking is often considered a risk factor for spontaneous abortion, the epidemiologic literature is actually inconsistent. Therefore, the authors examined maternal and paternal smoking and maternal passive smoke exposure using data from a large case-control study of spontaneous abortion (626 cases and 1,300 controls) conducted in Santa Clara County, California, in 1986 and 1987. No excess risk of spontaneous abortion was seen in the 1% of women who smoked an average of more than 20 cigarettes per day in the first trimester. Moderate smokers (11-20 cigarettes per day) had a slightly elevated crude odds ratio of 1.3 (95% confidence interval 0.9-1.9), which was close to unity after adjustment for covariates. Paternal smoking showed a slight crude elevation for moderate and heavy smoking, but no association after adjustment. In contrast, maternal exposure to environmental tobacco smoke for 1 hour or more per day was associated with spontaneous abortion, even after adjustment (odds ratio = 1.5, 95% confidence interval 1.2-1.9). For both maternal direct and environmental exposure, the association appeared to be stronger in second-trimester abortions. Several studies have found stronger associations of smoking with late versus early abortions, perhaps reflecting smoking-associated placental insufficiency and fetal hypoxia.

MeSH terms

  • Abortion, Spontaneous / etiology*
  • Case-Control Studies
  • Fathers
  • Female
  • Humans
  • Male
  • Mothers
  • Pregnancy
  • Smoking / adverse effects*
  • Tobacco Smoke Pollution / adverse effects


  • Tobacco Smoke Pollution