We tracked smoking outcomes -quitting, stage of readiness, action, motivation, self-efficacy, and confidenceover time among 943 low-SES women smokers accrued in an earlier smoking cessation intervention trial conducted in public health clinics. We assessed outcomes at 2, 6, 12 and 18 months post-initial clinic visit. Controlling for baseline characteristics and earlier program participation, we used hierarchical linear modeling to assess how intervening life events -pregnancy and exposure to subsequent clinic smoking interventions -affected smoking outcomes directly and indirectly, through the mediators, perceived stress and health concerns.Results: All longitudinal smoking outcomes were positively related to health concerns and negatively related to perceived stress. Pregnancy favorably influenced all smoking outcomes but confidence, but exposure to additional interventions affected only motivation. Health concerns and stress partially mediated the positive impact of pregnancy.Conclusion: Public health efforts targeted to low-SES women smokers should continue to emphasize the benefits of quitting smoking for health maintenance and incorporate more effective stress-coping mechanisms. Pregnancy increases abstinence, but preventing post-delivery relapse may require stress management and refocusing of health concerns.