OBJECTIVE: To compare incidence, risk factors, and etiology of women's deaths in fertile, subfertile, and undergoing assisted reproductive technology (ART) in the years after delivery. DESIGN: Retrospective cohort. SETTING: University hospital. PATIENT(S): Women who had delivered in Massachusetts. INTERVENTION(S): This study used data from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System linked to vital records, hospital stays, and the Massachusetts death file. Mortality of patients delivered from 2004-2013 was evaluated through 2015. The exposure groups, determined on the basis of the last delivery, were ART-treated (linked to Society for Assisted Reproductive Technology Clinic Outcome Reporting System), subfertile (no ART but with indicators of subfertility including birth certificate checkbox for fertility treatment, prior hospitalization for infertility [International Classification of Disease codes 9 628 or V23], and/or prior delivery with checkbox or ART), or fertile (neither ART nor subfertile). Numbers (per 100,000 women-years) and causes of death were obtained from the Massachusetts death file. MAIN OUTCOME MEASURE(S): Mortality of women after delivery in each of the three fertility groups and the most common etiology of death in each. RESULT(S): We included 483,547 women: 16,429 ART, 11,696 subfertile, and 455,422 fertile among whom there were 1,280 deaths with 21.1, 25.5, and 44.7 deaths, respectively, per 100,000 women-years. External causes (violence, accidents, and poisonings) were the most common reasons for death in the fertile group. Deaths occurred on average 46 months after delivery. When external causes of death were removed, there were 19.1, 17.0, and 25.6 deaths per 100,000 women-years and leading causes of death in all groups were cancer and circulatory problems. CONCLUSION(S): The study presents reassuring data that death rates within 5 years of delivery in ART-treated and subfertile women do not differ from those in fertile women.