BABY STEPS II: SMS Scheduled Gradual Reduction Text Messages to Help Pregnant Smokers Quit

Primary Aim: To test the efficacy of a SMS text-based scheduled gradual reduction (SGR) and counseling intervention to promote smoking cessation in the late third trimester. Hypothesis: The rate of smoking cessation in the late third trimester among women in the SGR Support Messages arm will be higher than among women in the Support Messages arm. Secondary Aim 1: To assess the effect of the SGR intervention on biochemically validated prolonged abstinence and smoking reduction during pregnancy. Secondary Aim 2: To assess the effect of the SGR intervention on smoking abstinence at three months postpartum. Secondary Aim 3: To assess the effect of the SGR intervention on the rate of preterm birth.