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.