Smoking during pregnancy has been linked to a variety of adverse outcomes for both maternal and child health. Decades of studies have sought to increase cessation antepartum and reduce relapse postpartum. A number of effective interventions exist to significantly reduce smoking rates during pregnancy; however, less is known about how to prevent relapse in the postpartum period. This review investigates interventions to prevent relapse in the long-term postpartum period. We focus specifically on nonspontaneous quitters (individuals who quit smoking as a result of an external intervention) to reveal differences in long-term response to interventions for this population compared to spontaneous quitters. A systematic literature search yielded 32 relevant studies of pharmacological, behavioral, and incentives-based interventions. Results were compiled, analyzed, and compared in order to evaluate success factors in maintaining cessation postpartum. Though intervention groups showed consistently higher quit rates during pregnancy than control groups, none of the intervention types were effective at preventing relapse in the longer-term postpartum period. One study maintained significantly higher abstinence in the longer-term period postpartum using a mix of behavioral and incentives strategies. Additional research in this area is needed to identify optimal intervention strategies to reduce long-term postpartum relapse, particularly for nonspontaneous quitters.