The authors describe the components of obstetrical nursing as the woman in the perinatal period, the existent problem, the context where the woman is assisted and the nursing care that is given to her. The emphasis is placed in the therapeutic nurse-patient relationship. The authors present instruments to support nursing care as observation, interviews, domiciliary visit, and the record of these three itens. To assure, as far as possible, the well-being of the binomial mother-child the nurse has to develope functions as guidance, therapeutic nurse-patient relationship, and crisis intervention.