<p>There is a lack of methods for quantifying moral distress which limits the possibility to address this emerging challenge in practice. The aims were to investigate the content and face validity of an adapted version of the Moral Distress Scale Reversed (MDS-R) for use in Swedish maternal and neonatal health care, to develop a criterion-based index for the identification of high moral distress, and to assess its relationship with stress, burnout complaints, intention to leave and job satisfaction. The content and face validity were assessed using expert assessments (<i>n</i> = 10) and cognitive interviews with experienced professionals (<i>n</i> = 5). A global moral distress index was developed using a criterion-based approach and survey data from maternal and neonatal healthcare workers (<i>n</i> = 951) within the longitudinal COPE Staff cohort were used for construct validity. Results showed good content and face validity. 28% reported high moral distress which was associated with increased levels of stress, burnout complaints and intention to leave, and with decreased levels of job satisfaction (<i>p</i> &lt; 0.001, respectively), indicating good construct validity. Thus, the Swedish maternal and neonatal version of the MDS-R may be used to systematically identify those at risk of adverse effects due to high moral distress, enabling early intervention and prevention.</p>