Objective: to construct and validate an instrument to assist the nursing consultation of pregnant women with diabetes mellitus. Methods: methodological study involving the construction of an instrument and evaluation by expert judges in the area who delivered opinions on the objectives, structure, presentation, relevance and content of the instrument of each item. Results: the instrument obtained a satisfactory evaluation in the evaluated criteria, obtaining an index of validity of general content above 85.0% and index of content validity above 80.0% in most of the items. Five items were modified according to the recommendations provided by the judges. Conclusion: the content of the instrument was considered valid to guide the nursing consultation, favoring the promotion of quality of life, adoption of healthy life habits and self-care practices, and provides glimpses of emotional, psychological and social aspects that may influence the endocrine modifications during gestation.