We have previously reported women's perceptions of their experience with fetal intrapartum oxygen saturation monitoring and participation in a research project, assessed within a few days of delivery when the "halo effect' may have influenced responses. To determine whether women's perceptions had changed over time, we sent a second, identical questionnaire to the 49 women in the original sample who had delivered 3-12 months previously. Thirty-eight questionnaires were returned. Wilcoxon signed rank sum test was used to compare the ratings. Women's responses to the first and second questionnaire were not significantly different. Written comments were provided by 23 (61%) of the women. This stability of women's perceptions over time suggests that the original practice of surveying within a few days of delivery accurately reflects women's evaluation of their experience with the research project.