Our purpose was to assess the effect of prenatal smoking interventions on rates of smoking cessation. A total of 37 trials, conducted between 1976 and 2002 and comprising over 14000 women were identified and included in the meta-analyses. There was a significant increasing in the odds of women who quit smoking in late pregnancy in the intervention group (OR = 1.6; 95% CI 1.4-1.8). The effectiveness of the intervention was significantly higher in the studies that smoking cessation intervention included written materials for pregnant women then in the studies without those materials. The percentage of pregnant women who quit smoking was higher among American women than among women from the European Countries.