Smoking during pregnancy is the leading preventable cause of perinatal morbidity and mortality.1 The dissemination of health warnings has been associated with a decline in prenatal smoking over the past several decades.2 3 Yet, approximately one fourth of US women of childbearing age currently smoke and only a third of them will quit for pregnancy.3 4 Women smoking at the time they become pregnant are known as pre-pregnancy smokers. Most women who stop smoking for pregnancy do so on their own before they initiate prenatal care and are called spontaneous quitters. Compared to women still smoking (intake smokers), spontaneous quitters more often are younger, having their first baby, have completed more years of education, are more …