RecruitingPhase 4Drug trialModifying Progesterone and Estradiol Levels to Prevent Postpartum Cigarette Smoking Relapse and Reduce Secondhand Smoke Exposure in Infants and ChildrenThe investigators aim to address the following specific aims: * Determine the efficacy of Prog in preventing postpartum smoking relapse and reducing smoking relapse risk factors. * Examine the effects of this maternal smoking intervention on infant health. * Examine racial and ethnic differences in intervention outcomes.