Currently, no data are available using standardized instruments for evaluating the postpartum mental health of women with previous bariatric surgery. The aim of this pilot study was to assess postpartum mental health in women following bariatric surgery and to establish appropriate tools for a prospective registry study in the future. In this survey, the mental health of 22 women during the first weeks postpartum was examined (T1) and their status at least 6 months after childbirth was prospectively assessed (T2). Symptoms of depression and anxiety were evaluated with standardized questionnaires and depression was diagnosed with structured diagnostic interviews (SCID-5). At T1, 3/22 women (14%) reported depressive or anxiety symptoms, and in these women, the diagnosis of depression was established. In comparison with T1, at T2, symptomatology for depression or anxiety increased to 32% and 27% of patients, respectively, but only one woman was diagnosed with depression. In comparison to patients without symptoms, patients with signs of depression or anxiety or both had lower total body weight loss and, more often, a personal or family history of depressive disorders. Our pilot study suggests that the rate of postpartum depression in women after BS might be higher than in the general population. High symptom levels of depression and anxiety emphasize the necessity of long-term bariatric follow-up care. Further research is needed to evaluate if prevalence of depression or anxiety disorder or both is higher in this patient group as compared to other patients after bariatric surgery.