A systematic review of couple- or household-targeted interventions for smoking cessation in pregnancy

BACKGROUND: Tobacco smoking is a major modifiable risk for poor pregnancy outcomes. Pregnant women whose partner smokes are six times more likely to continue smoking. Typically, interventions target pregnant mothers or smoking fathers to reduce second-hand smoke exposure. Evidence reviews advocate for couple-targeted smoking cessation interventions, however no recent review has evaluated the effectiveness of interventions targeting both pregnant women and their partner/household member. We aimed to systematically review and evaluate the effectiveness of smoking cessation interventions targeting the couple/household where both parties smoke for antenatal smoking cessation in pregnant women. METHODS: We searched 8 databases (MEDLINE, Embase, Emcare, AMED, BNI, CINAHL, PsycINFO, Cochrane Register of Controlled Trials) for randomised controlled trials (RCTs), controlled non-randomised studies and before-and-after studies, meeting PICO criteria: Population: pregnant woman and her partner/household member/s who are tobacco smokers antenatally. INTERVENTION: Tobacco smoking cessation intervention targeting a couple/household. CONTROL: Intervention targeting woman only, usual care, historical control group. Outcome/s: Objectively assessed or self-reported antenatal maternal smoking cessation. Studies were systematically selected for inclusion and data were extracted by two researchers. Meta-analysis was not undertaken due to clinical and methodological heterogeneity, including differing intervention types, outcome measures, cut-offs used to define cessation and follow-up timepoints. Data were narratively synthesised. RESULTS: Six studies were included: 4 RCTs, 1 non-randomised comparative study and 1 before-and-after study. Interventions were poorly described, variable in content across studies, and differed in content between women and partners/household members within studies. They included behavioural support (n = 6 women, n = 4 partners), written or self-help materials (n = 4 women, n = 6 partners), nicotine replacement therapy (n = 1 women, n = 1 partners), demonstration of smoking effects on the fetal heart (n = 1 women) and incentives (n = 1 women). Three studies directly targeted partners and three targeted them indirectly via the woman. Only one study compared targeting the couple versus the woman only. Varied subjective and objective cessation measures were assessed. Quit definition, measurement timepoint, and whether partner cessation was evaluated varied. Two RCTs, one non-randomised controlled and one before-and-after study reported that their intervention positively impacted smoking cessation for women compared with usual care. One RCT reported increased cessation for intervention versus control for partners. CONCLUSIONS: Few up-to-date studies have evaluated smoking cessation interventions targeting couples/households who smoke during pregnancy. Interventions rarely directly target partners. Interventions directly targeting the woman and her partner or smoking household members, using up-to-date interventions (e.g., nicotine replacement therapy, vapes, behavioural support) are yet to be assessed in high quality studies and more evidence in this field is needed. Standardised outcomes for both women and partners are needed to evaluate efficacy, identify the active components of interventions and facilitate evidence syntheses.