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Keywords:

  • Birth outcomes;
  • birth weight;
  • cigarette smoking;
  • contingency management;
  • gestational age;
  • low birth weight;
  • preterm birth;
  • smoking cessation;
  • vouchers

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.