CIGARETTE SMOKING DURING PREGNANCY AND THE OCCURRENCE OF SPONTANEOUS ABORTION AND CONGENITAL ABNORMALITY

A multiple logistic regression analysis of 12,914 pregnancies and 10,523 live births, based on a mail survey of professional women in medicine, was carried out to determine the relationship between maternal cigarette smoking, and spontaneous abortion and congenital abnormality. After controlling for interfering variables (age, exposure to trace anesthetic gases, pregnancy history, and mailing response), a statistically significant increase in risk associated with maternal cigarette smoking was found for spontaneous abortions and congenital abnormalities. The risk of spontaneous abortion for the heavy smoker is estimated to be as much as 1.7 times that of the nonsmoker in certain risk groups. The risk for congenital abnormality for babies born of smoking mothers is estimated to be as much as 2.3 times that of the nonsmoker, depending on age, pregnancy history, and other factors.In an effort to determine the relationship between maternal cigarette smoking, and spontaneous abortion and congenital abnormality, a multiple logistic regression analysis of 12,914 pregnancies and 10,523 live births, based on a mail survey of professional women in medicine, was conducted. The multiple logistic regression model, with certain interactions, appears to fit the spontaneous abortion and abnormality data well. The model provides an efficient method for adjusting for many variables, and on the basis of this approach, the following conclusions are drawn: 1) the survey data provide statistically significant indication that the risk of spontaneous abortion is substantially higher for women who smoke during pregnancy; 2) an analysis of the congenital abnormality data shows a statistically significant risk associated with maternal smoking - the relative risk ranges from 0.8 to 2.3 times that of the non-smoker, depending on age, previous pregnancy history, and exposure to the operating room. Despite the fact that the findings are retrospective survey data, obtained by mail and subject to variation in response due to the experience and background of the participant, the study confirms previous reports indicating that smoking is positively correlated with spontaneous abortion and provides evidence of a large increase in the risk of congenital abnormalities for the child born of a smoking mother.