Pregnancy represents a high information need state, where uncertainty around medical intervention is common. As such, women often engage in vaccine information-seeking behaviour, a process that involves the gathering and use of information to inform the vaccine decision-making process. If this seeking occurs outside of official healthcare system channels, many healthcare professionals are concerned that this behaviour may lead women towards less reliable, potentially misleading information. The concept of vaccine information-seeking during pregnancy therefore warrants examination. In this thesis, I present two systematic reviews and two quantitative research papers related to the topic of vaccine information-seeking behaviour. These studies investigate the predictors of and influences on vaccine information-seeking behaviour both in general and specifically relating to UK women making a decision regarding the pertussis vaccination for pregnant women. In the systematic reviews, I synthesise the literature related to the measurement of trust in vaccination and how vaccine information-seeking behaviour has previously been investigated throughout the vaccine attitude and decision-making literature. The literature from these two review papers informed the design of two quantitative questionnaire studies. The first of these investigates the determinants of satisfaction with official information and the additional information-seeking behaviour of recently pregnant women in regards to the pertussis vaccination given during pregnancy. The second investigates how previously held attitudes towards vaccination influence vaccine information-seeking behaviour, and how such behaviours may in turn influence the vaccine decision-making process. Findings from the first quantitative study indicate that a higher trust in one’s healthcare professional, a perceived ability to seek out accurate information about vaccines, and actively engaging with problems as a means of coping with stress, predicts satisfaction in the official vaccine information. While a large minority (approximately 40%) of women searched for additional information about the pregnancy pertussis vaccine during their pregnancy, neither satisfaction related to official information, nor attitudes towards vaccination, predicted vaccine information-seeking behaviour. From my second quantitative study, the length of time that individuals spend seeking information was associated with a higher perceived risk of pertussis disease and a lower confidence in vaccination. Intention to vaccinate was found to relate to the perceived influence of such found information, with higher intention to vaccinate being associated with respondents reporting that the information they found pointed them towards vaccination and lower levels of intention to vaccinate being associated with respondents reporting that the information they found pointed them away from vaccination. When I examined attitudes across the course of a pregnancy, a significant shift in risk perception occurred whereby women became more risk averse to the disease of pertussis as compared to the vaccine that protects against pertussis. This shift was not found to be associated with vaccine information-seeking behaviour, strength of vaccine recommendation for respondent’s healthcare professional or vaccine uptake. This line of research demonstrates the role of vaccine information-seeking behaviour within the vaccine decision making process. Information related to the pertussis during pregnancy vaccination is rarely judged on its own intrinsic qualities instead it is viewed through a range of pre-existing beliefs and social contexts. With midwives being the health care professional that conducts the majority of the vaccine communication in regards to this particular programme, it is vital that midwives are given the time and available resources to build strong relationships with their patients and feel that they have the self-efficacy to effectively communicate vaccine information. This would undoubtably be of benefit to the pertussis during pregnancy vaccination programme, but would also better guide women towards reliable information sources in regards to subsequent childhood vaccinations.