Smoking during pregnancy has been linked to health problems, including the risk of low birthweight, preterm labour, spontaneous abortion and perinatal death. Two trials to investigate the efficacy of self-help materials were undertaken. During the first trial, a self-help booklet developed overseas was evaluated through a randomised controlled design to determine the effects of the booklet alone, compared with the booklet with midwife counselling for the women. We recruited 217 women into the study and followed them up at 20 weeks' gestation to ascertain smoking cessation and to measure process variables. Smoking cessation rates were lower than expected, and process measures indicated that materials were not being used. A second trial was commenced after a comprehensive review of the materials with focus groups of pregnant women and one-to-one interviews of nurses and doctors. Trial 2 was based new materials, and used a magazine-style (smoking cessation) booklet designed by the focus groups. A total of 119 women were randomly allocated into the new-materials group or a usual-care group. The materials were well received, relevant and pertinent, and were used by the women. Smoking cessation rates at 20 weeks' gestation were biochemically validated and indicated that 9 per cent in the intervention group and none in the usual-care group had stopped smoking. The use of overseas programs needs to be approached with caution.