Nearly 443,000 U.S. deaths are attributable annually to cigarette smoking, which makes tobacco, including secondhand smoke, the most preventable cause of disease, disability, and death in the U.S. An estimated 19.8 million women in the U.S. smoke. Smoking during pregnancy can result in significant complications for the pregnant woman, her fetus, and members of the woman's household who are exposed to secondhand smoke. Smoking is associated with increased risk of placental abruption, anemia, preterm birth, chronic hypertension, and placenta previa. Health risks to the fetus include low birth weight, restricted growth, and fetal death. Multiple interventions to promote smoking cessation exist. They include advice and counseling, self-help materials, nicotine replacement therapy (NRT), antidepressants including bupropion (Zyban(R)), and pharmacologic cessation aids such as varenicline (Chantix(R)). The American College of Obstetricians and Gynecologists does not recommend pharmacologic interventions as first-line therapies in pregnant women due to lack of evidence on safety and efficacy. Overall, the findings from existing systematic reviews suggest that NRT, behavioral and educational cessation strategies, and multicomponent interventions may be beneficial to women who smoke in pregnancy or the postpartum period, but to date, evidence has been mixed. Despite these previous systematic review efforts, however, the efficacy of specific components and the impact of these various strategies on smoking and infant outcomes in pregnant and postpartum women remain unclear. This review is focused on the evidence available to inform the provision of smoking cessation strategies for health care providers. Interventions include any behavioral, psychosocial, pharmacologic, or educational intervention intended to promote individual changes in cigarette consumption among pregnant smokers and recent quitters in the prenatal and postpartum period. Interventions targeting the behavior of smokers' partners or health care providers exclusively were not included. Interventions of interest are those that were conducted in or originated from a health care setting. Smoking outcomes are limited to biochemically validated reports of smoking cessation during pregnancy or in the postpartum period. Biochemical validation of smoking status includes measures of cotinine from saliva, urine, or serum; expired carbon monoxide; or serum thiocyanate. Although these measures do not verify continuous abstinence, they are accepted standards for evaluating point prevalence of smoking status. Key Questions addressed: 1: What is the effectiveness of interventions intended to achieve or maintain smoking cessation in women who are pregnant or postpartum for promoting smoking cessation, relapse prevention, and continuous abstinence? 2: What is the effectiveness of interventions intended to achieve or maintain smoking cessation in women who are pregnant or postpartum for improving infant and child outcomes? 3: What are the harms of interventions intended to achieve or maintain smoking cessation in women who are pregnant or postpartum? 4: What is the effect of components of the smoking cessation intervention, including who delivered the intervention (physician, nurse, midwife, etc.), the intervention itself, and where the intervention was delivered (clinic, hospital setting, etc.), on cessation of smoking or durability of cessation in women who are pregnant or postpartum? 5: What is the effect of patient characteristics on outcomes of smoking cessation interventions (successful/unsuccessful cessation, relapse) in women who are pregnant or postpartum?