Abstract. The transition to motherhood is an important moment in the life course, in which symbolic interactive dynamics are established between self, other, and world to overcome developmental challenges. However, these challenges are intensified with the COVID-19 pandemic, which caused a radical and unexpected rupture in daily life. This article aims to analyze the affective-semiotic dynamics of Brazilian women who experienced the transition to motherhood during the COVID-19 pandemic from a qualitative multiple case study. Eight women participated in the study in the city of Salvador. Data were collected from two narrative interviews with each participant conducted through videoconference, with a 2-month interval between interviews. The main finding reveals that the emergence of the pandemic was described by the participants as an unexpected and significant rupture in the transition to motherhood that raised feelings of fear and anxiety. In addition, I–other relations were marked by intense ambivalence between the need for social support and the risk of contagion, and the perspective and experience of childbirth were marked by a feeling of insecurity in the relations with the health personnel and settings. In light of Semiotic Cultural Psychology, three interdependent affective-semiotic fields were highlighted from the narratives: the perception of oneself regulated by the sign of vulnerability, the other regulated by the sign of a potential threat, and healthcare provision regulated by the sign of risk. These findings highlight the importance of quality healthcare that helps women to reduce the disruptive impact of the pandemic on the ontogenetic structure of psychological organization.