Background: Pregnant women with one previous caesarean section (CS) must consider their preference for mode of delivery. For most this involves a choice between attempted vaginal birth after caesarean (VBAC) and elective CS. Decision aids are interventions designed to assist patients to make treatment choices and have been shown to be beneficial in a variety of health settings. Aim: To design and evaluate two computer-based decision aids to assist pregnant women with one previous CS with decision making about preferred mode of delivery. Methods: This thesis reports four components of the research 1) A qualitative interview study involving 21 postnatai women which explored women's experiences of decision making. 2) The developm~ntoftwo computer-based decision aids by a multidisciplinary team. 3) A qualitative piloting study involving 15 postnatal and 11 antenatal women. 4) A randomised controlled trial (RCT) to evaluate the two decision aids (Information Program or Decision Analysis Program) compared to usual care. 742 women with one previous CS participated in the RCT. The primary outcomes were decisional conflict at 37 weeks' gestation and actual mode of delivery. Results: The interview study established a need for the decision aids by highlighting potential inadequacies in the provision of information in routine care. The piloting study showed that the proposed decision aids were acceptable, usable and comprehensive. The RCT demonstrated that both decision aids reduced decisional conflict compared with usual care. There was also a suggestion that the VBAC rate was higher amongst women in the Decision Analysis Program group, in comparison with both other groups. Discussion: Pregnant women with one previous CS were found to benefit from access to either of the decision aids in addition to their routine clinical care. Further investigation is required ~o confirm whether the Decision Analysis Program could help to reduce the discrepancy between women's preferred and actual mode of delivery. Issues relating to the implementation of the decision aids must also be considered.