title: Effects of voucher-based incentives on abstinence from cigarette smoking and fetal growth among pregnant women.
abstract: OBJECTIVE
  This study examined whether voucher-based reinforcement therapy (VBRT) contingent upon smoking abstinence during pregnancy is an effective method for decreasing maternal smoking during pregnancy and improving fetal growth.
  
  
  METHODS
  A two-condition, parallel-groups, randomized controlled trial was conducted in a university-based research clinic. A total of 82 smokers entering prenatal care participated in the trial.
  
  
  METHODS
  Participants were assigned randomly to either contingent or non-contingent voucher conditions. Vouchers exchangeable for retail items were available during pregnancy and for 12 weeks postpartum. In the contingent condition, vouchers were earned for biochemically verified smoking abstinence; in the non-contingent condition, vouchers were earned independent of smoking status.
  
  
  METHODS
  Smoking outcomes were evaluated using urine-toxicology testing and self-report. Fetal growth outcomes were evaluated using serial ultrasound examinations performed during the third trimester.
  
  
  RESULTS
  Contingent vouchers significantly increased point-prevalence abstinence at the end-of-pregnancy (41% versus 10%) and at the 12-week postpartum assessment (24% versus 3%). Serial ultrasound examinations indicated significantly greater growth in terms of estimated fetal weight, femur length and abdominal circumference in the contingent compared to the non-contingent conditions.
  
  
  CONCLUSIONS
  These results provide further evidence that VBRT has a substantive contribution to make to efforts to decrease maternal smoking during pregnancy and provide new evidence of positive effects on fetal health.
authors.affiliation: Departments of Psychiatry, University of Vermont, Burlington, VT 05401, USA. sarah.heil@uvm.edu
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Heil
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Higgins
authors.forename: Ira M
authors.initials: IM
authors.lastname: Bernstein
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Solomon
authors.forename: Randall E
authors.initials: RE
authors.lastname: Rogers
authors.forename: Colleen S
authors.initials: CS
authors.lastname: Thomas
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Badger
authors.forename: Mary Ellen
authors.initials: ME
authors.lastname: Lynch
mesh_terms: D000328:Adult; D001944:Breath Tests / Q000379:methods; D005260:Female; D047109:Fetal Development / Q000187:drug effects; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D009042:Motivation; D010349:Patient Compliance; D011247:Pregnancy; D012907:Smoking / Q000009:adverse effects / Q000523:psychology; D016540:Smoking Cessation / Q000379:methods* / Q000523:psychology; D000074606:Smoking Prevention; D014040:Token Economy; D016896:Treatment Outcome