The issue of precarious living conditions is a new focus for the ENCMM. In light of the perceived increase in the number of maternal deaths that may be linked to precarious living conditions, we sought to identify the key factors that could contribute to maternal death in this context, with the aim of proposing a definition. The selection of cases made retrospectively is primarily based on a qualitative assessment. Between 2010 and 2012, among the cases reviewed by the CNEMM, one or more factors related to social vulnerability were identified in 8.6% of cases (18 deaths). The direct criteria selected were the concepts of “precariousness” or “social difficulties,” housing difficulties, language barriers, and isolation. Lack of prenatal care was selected as an indirect marker. We excluded cases where a psychiatric condition and/or one or more addictions were predominant. Of the 18 cases identified with factors of precariousness, the death was considered “inevitable” in 2 cases (11%), “certainly preventable” or “possibly preventable” in 13 cases (72%). In 3 cases (17%), preventability could not be determined. Preventability was related to the content and adequacy of care (11 out of 13 cases, 85%) and to the patient’s interaction with the healthcare system in 10 out of 18 cases (56%). Analysis of maternal deaths among women in precarious situations serves as a reminder that the link between socioeconomic precariousness and poor maternal health outcomes potentially includes a specific risk of maternal death.