This paper explores the potential implications of embodied conversational agents (ECAs) in healthcare, focusing on the impact of appearance and conversation style on trustworthiness. We conducted a Research through Design investigation of ECAs for supporting women during the periconception period and in pregnancy. The paper presents the results of a Wizard of Oz study in which two alternative prototypes, a chatbot, and an ECA, were tested in a tertiary hospital by 25 participants. Reflecting on the results we suggest that limited patients' trust in ECAs maybe be beneficial for achieving trustworthy use of these agents in the healthcare context. @en