Objectives: We tested the effect of nurse-delivered telephone individualized social support ("Baby BEEP") and eight mailed prenatal smoking cessation booklets singly and in combination (2 x 2 factorial design) on smoking cessation in low-income rural pregnant women (N = 695; 75% participation).
Methods: Participants randomized to Baby BEEP groups (n = 345) received weekly calls throughout pregnancy plus 24-7 beeper access. Saliva cotinine samples were collected monthly from all groups by other nurses at home visits up to 6 weeks post-delivery. Primary outcomes were point prevalence abstinence (cotinine < 30 ng/ml) in late pregnancy and post-delivery.
Results: Only 47 women were lost to follow-up. Intent-to-treat analyses showed no difference across intervention groups (17-22%, late pregnancy; 11-13.5%, postpartum), and no difference from the controls (17%, late pregnancy; 13%, postpartum). Post hoc analyses of study completers suggested a four percentage-point advantage for the intervention groups over controls in producing early and mid-pregnancy continuous abstainers. Partner smoking had no effect on late pregnancy abstinence (OR = 1.7, 95% CI = 0.95, 3.2), but post-delivery, the effect was pronounced (OR = 3.2, 95% CI = 1.8, 5.9).
Conclusions: High abstinence rates in the controls indicate the power of biologic monitoring and home visits to assess stress, support, depression, and intimate partner violence; these elements plus booklets were as effective as more intensive interventions. Targeting partners who smoke is needed.