Smoking during pregnancy and hospitalization of the child.

OBJECTIVES To study the association between smoking during pregnancy and hospitalization of the child before 8 months of age. DESIGN A follow-up study of 1974 children born in 1991 and 1992. RESULTS Overall, 158 (8%) of the children were hospitalized during the first 8 months of life. Compared with children whose mothers did not smoke during pregnancy, children with mothers who smoked 1 to 14 cigarettes per day had no increased risk of being hospitalized (relative risk: 1.1; 95% confidence interval: 0.8-1.5), whereas children whose mothers smoked 15 or more cigarettes per day had twice as high a risk of being hospitalized (relative risk: 2.0; 95% confidence interval: 1.2-3.3). When only hospitalizations before 2 months of age were analyzed, smoking during pregnancy was associated an increased risk similar to that described above. Hospitalization of the child was independent of the smoking habits of the father, and an increased risk of hospitalization associated with smoking was found not only among children with symptoms from the respiratory system but also among children with symptoms from the gastrointestinal system and the skin. The association between smoking during pregancy and hospitalization of the child persisted after adjustment for postpartum smoking habits and a number of socio-demographic and lifestyle factors. CONCLUSIONS Smoking 15 or more cigarettes per day during pregnancy influenced the health of the children, and several points indicated that the effect of in utero exposure was independent of postpartum smoking habits. If all pregnant women smoking 15 or more cigarettes per day stopped smoking, approximately 5% of all admissions to hospitals before 8 months of age could be avoided. smoking during pregnancy, hospitalization of children.