The specific aims of the current maintenance study are: 1) to compare biochemically confirmed smoking abstinence rates of women who quit smoking during their pregnancy and who receive an intervention based on telephone counseling using motivational interviewing versus quitters who receive usual care, maintenance of abstinence will be assessed at 1, 3, 6, and 12 months postpartum; and 2) to collect both qualitative and quantitative data to better understand short term and long term maintenance mediators and moderators of abstinence postpartum for women of low socioeconomic status (SES) who quit smoking during pregnancy.