Effects of smoking cessation with voucher-based contingency management on birth outcomes

Abstract

Aims: This study examined whether smoking cessation using voucher-based contingency management (CM) improves birth outcomes.

Design: Data were combined from three controlled trials.

Setting: Each of the trials was conducted in the same research clinic devoted to smoking and pregnancy.

Participants: Participants (n=166) were pregnant women who participated in trials examining the efficacy of voucher-based CM for smoking cessation. Women were assigned to either a contingent condition, wherein they earned vouchers exchangeable for retail items by abstaining from smoking, or to a non-contingent condition where they received vouchers independent of smoking status.

Measurement: Birth outcomes were determined by review of hospital delivery records.

Findings: Antepartum abstinence was greater in the contingent than non-contingent condition, with late-pregnancy abstinence being 34.1% versus 7.4% (P<0.001). Mean birth weight of infants born to mothers treated in the contingent condition was greater than infants born to mothers treated in the non-contingent condition (3295.6 ± 63.8 g versus 3093.6 ± 67.0 g, P = 0.03) and the percentage of low birth weight (<2500 g) deliveries was less (5.9% versus 18.5%, P = 0.02). No significant treatment effects were observed across three other outcomes investigated, although each was in the direction of improved outcomes in the contingent versus the non-contingent condition: mean gestational age (39.1 ± 0.2 weeks versus 38.5 ± 0.3 weeks, P = 0.06), percentage of preterm deliveries (5.9 versus 13.6, P = 0.09), and percentage of admissions to the neonatal intensive care unit (4.7% versus 13.8%, P = 0.06).

Conclusions: These results provide evidence that smoking-cessation treatment with voucher-based CM may improve important birth outcomes.