A randomized controlled trial of smoking cessation for pregnant women to test the effect of a transtheoretical model-based intervention on movement in stage and interaction with baseline stage.
OBJECTIVE
To examine whether, as predicted by the transtheoretical model (TTM), stage-matched interventions will be more effective than stage-mismatched interventions.


METHODS
Randomized controlled trial of smoking cessation advice to pregnant smokers.


METHODS
Pregnant women currently smoking at 12 weeks gestation were enrolled in a pragmatic three-arm trial of TTM-based interventions to help them stop smoking. One arm constituted standard midwifery advice and a self-help leaflet on stopping smoking, which is generally appropriate for women in preparation. Two arms were TTM-based. Differences in positive movement in stage towards quitting from enrolment to 30 weeks gestation and 10 days post-partum were calculated for each arm of the trial. We then examined whether, as predicted from the TTM, the relative benefit of the TTM-based intervention was greater for women in precontemplation and contemplation, for whom the control intervention was stage-mismatched, than for women in preparation, for whom the control intervention was stage-matched.


RESULTS
Women in the TTM-based arms were statistically significantly more likely to move forward in stage than were women in the control arm. Contrary to the TTM-derived hypothesis, the greater relative benefit of the TTM-based intervention was seen for women in preparation stage at baseline, rather than women in precontemplation and contemplation.


CONCLUSIONS
The TTM-based intervention was more effective in stage movement, but this could be due to its greater intensity. The failure to confirm that stage-matching was important casts doubt on the validity of the TTM in explaining smoking cessation behaviour in pregnancy.
Aveyard
Paul
P
Department of Public Health and Epidemiology, University of Birmingham, UK. p.n.aveyard@bham.ac.uk
Lawrence
Terry
T
Cheng
K K
KK
Griffin
Carl
C
Croghan
Emma
E
Johnson
Carol
C
D000293:Adolescent; D000328:Adult; D003376:Counseling; D005260:Female; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D033182:Intention; D008875:Middle Aged; D008880:Midwifery; D010174:Pamphlets; D010353:Patient Education as Topic; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D037841:Pregnant People / Q000523:psychology*; D011295:Prenatal Care / Q000379:methods*; D011582:Psychological Theory; D012648:Self Care / Q000523:psychology; D016540:Smoking Cessation / Q000523:psychology*; D013664:Teaching Materials