IntroductionPerinatal depression is a leading cause of preventable US maternal morbidity and mortality. Although Mindfulness‐Based Cognitive Therapy for Perinatal Depression (MBCT‐PD) is highly effective, it faces significant scalability challenges. Center M, a brief, group‐based, mindfulness‐based cognitive behavioral therapy (CBT) intervention, is an adaptation of MBCT‐PD designed to overcome these challenges. The purpose of this pilot study was to evaluate Center M's preliminary acceptability, feasibility, mechanisms of action, and efficacy.MethodsIn this mixed‐methods pilot study, data were collected from 99 pregnant people at 3 time points: preintervention, postintervention, and 6‐weeks postpartum (Clinical Trials no. NCT06525922). Participants engaged in 4 one‐hour, weekly group telehealth Center M sessions facilitated by social workers. Participants strengthened mindfulness CBT skills using home practice materials between group sessions. Data included self‐report measures evaluating depressive symptoms, mindfulness skills, and emotion regulation. Satisfaction was assessed via focus groups or surveys.ResultsDepressive symptoms significantly decreased preintervention to postintervention (Patient Health Questionnaire‐8 score: preintervention mean [SD] 5.02 [3.52], postintervention mean [SD] 4.23 [2.84]; P = .03), and mindfulness capacity significantly increased preintervention to 6 weeks postpartum (Five Facets of Mindfulness Questionnaire score: preintervention mean [SD] 125.56 [18.68], 6 weeks postpartum mean [SD] 130.10 [17.15]; P = .004). Linear regression analyses indicate that higher mindfulness at 6 weeks postpartum significantly predicted fewer depression symptoms at 6 weeks postpartum (β, −0.07; 95% CI, −0.123 to −0.021, R2 = 0.22; P = .006). Reduction in the use of maladaptive emotion regulation was significantly associated with decreased depressive symptoms at 6 weeks postpartum (β, 0.21; 95% CI, 0.048 to 0.376, R2 = .21; P = .012). Qualitative themes indicated high Center M acceptability and appeal.DiscussionOur findings support the feasibility, acceptability, and appeal of Center M. Results suggest Center M may be effective in reducing depression and enhancing mindfulness skills. Future research must confirm these initial findings to more widely address Center M implementation capacity and sustainability.