Contingency Management Interventions for Abstinence from Cigarette Smoking in Pregnancy and Postpartum: A Systematic Review and Meta-analysis

Contingency management is one of the most effective treatments for substance use disorders in not-pregnant people. The most recent quantitative review of its efficacy among pregnant and postpartum women who smoke cigarettes concluded with moderate certainty that those receiving contingent financial incentives were twice as likely to be abstinent compared with controls. We aimed to update and extend previous reviews. Five databases were systematically searched for randomized controlled trials (RCTs) published before December 2022 that assessed the effectiveness of incentives for abstinence from substance use. Data from trials of smoking abstinence were pooled using a random-effects meta-analysis model (restricted maximum likelihood). Results are reported as risk-ratios (RRs) with 95% confidence intervals (CIs). This study is registered with PROSPERO, CRD42022372291. Twelve RCTs (3136) pregnant women) were included. There was high certainty evidence that women receiving incentives were more likely to be abstinent than controls at the last antepartum assessment (12 RCTs; RR = 2.43, 95% CI 2.04-2.91, n = 2941, I = 0.0%) and moderate certainty evidence at the longest postpartum assessment while incentives were still available (five RCTs; RR = 2.72, 1.47-5.02, n = 659, I = 44.5%), and at the longest postpartum follow-up after incentives were discontinued (six RCTs; RR = 1.93, 1.08-3.46, n = 1753, I = 51.8%). Pregnant women receiving incentives are twice as likely to achieve smoking abstinence during pregnancy suggesting this intervention should be standard care for pregnant women who smoke. The results also demonstrate that abstinence continues into the postpartum period, including after incentives are discontinued, but more trials measuring outcomes in the postpartum period are needed to strengthen this conclusion.