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.