Perinatal mood and anxiety disorders are among the most common complications that occur in pregnancy or in the first 12 months after delivery. Despite the negative effects on maternal, obstetric, birth, offspring, partner, and family outcomes, perinatal mental health disorders often remain underdiagnosed, and untreated or under-treated. ACOG recognizes the importance of educational tools to help ob-gyns and other women’s health care professionals address perinatal mental health conditions. To this end, ACOG is sharing the Lifeline for Moms Perinatal Mental Health Tool KitTM, developed by the UMass Chan Medical School and reviewed by members of ACOG’s Maternal Mental Health Expert Work Group, to provide actionable information, algorithms, and clinical pearls to support detection, assessment, and treatment of perinatal mood and anxiety disorders.