Aim: Despite research suggesting increased anxiety and depressive symptoms after a perinatal loss and during future pregnancies, little knowledge exists to guide clinicians treating pregnant women after perinatal loss. This case study explores processes that facilitated therapeutic change for a pregnant patient with major depressive disorder (MDD) and posttraumatic stress disorder after perinatal losses. Method: The study integrated quantitative and narrative analyses in a single case derived from the pilot phase of a randomized controlled trial on supportive-expressive therapy for MDD. Results: The quantitative and narrative analyses suggest that an improvement in maladaptive interpersonal patterns toward the therapist, in the form of attachment avoidance, made it possible to form a strong alliance, which in turn led to a successful outcome. Conclusions: The findings highlight the importance of improving maladaptive interpersonal patterns as a prerequisite to enable patients after pregnancy losses to develop and maintain a corrective therapeutic experience.