ImportanceThe US has the highest maternal mortality rate among developed countries. The Centers for Disease Control and Prevention deems nearly all of these deaths preventable, especially those attributable to mental health conditions. Coordination between US health care and social service systems could help further characterize circumstances and risks associated with perinatal suicide mortality.ObjectiveTo examine contextual and individual precipitating circumstances and risks associated with perinatal suicide.Design, Setting, and ParticipantsThis cross-sectional observational study used a convergent mixed methods design to explore factors contributing to maternal suicides and deaths of undetermined intent (hereinafter, undetermined deaths) identified in National Violent Death Reporting System (NVDRS) data for January 1, 2003, to December 31, 2021. Analyses included decedents who were aged 10 to 50 years and pregnant or post partum at death (collectively, the perinatal group) and demographically matched female decedents who were not pregnant or recently pregnant (nonperinatal group) at death. Analyses were performed between December 2022 and December 2023.ExposuresPregnancy status at death (perinatal or nonperinatal).Main Outcomes and MeasuresThe main outcomes included contributing circumstances associated with suicides and undetermined deaths cited in coroner, medical examiner, or law enforcement case narratives. The study examined quantitative differences between groups using a matched analysis and characterized key themes of salient suicide circumstances using qualitative content analysis.ResultsThis study included 1150 perinatal decedents identified in the NVDRS: 456 (39.6%) were pregnant at death, 203 (17.7%) were pregnant within 42 days of death, and 491 (42.7%) were pregnant within 43 to 365 days before death, yielding 694 postpartum decedents. The nonperinatal comparison group included 17 655 female decedents aged 10 to 50 years. The mean (SD) age was 29.1 (7.4) years for perinatal decedents and 35.8 (10.8) years for nonperinatal decedents. Compared with matched nonperinatal decedents, perinatal decedents had higher odds of the following identified contributing circumstances: intimate partner problems (IPPs) (odds ratio [OR], 1.45 [95% CI, 1.23-1.72]), recent argument (OR, 1.33 [95% CI, 1.09-1.61]), depressed mood (OR, 1.39 [95% CI, 1.19-1.63]), substance abuse or other abuse (OR, 1.21 [95% CI, 1.03-1.42]), physical health problems (OR, 1.37 [95% CI, 1.09-1.72]), and death of a family member or friend (OR, 1.47 [95% CI, 1.06-2.02]). The findings of the qualitative analysis emphasized the importance of mental health and identified 128 decedents (12.4%) with postpartum depression.Conclusions and RelevanceThis study provides insights into complex factors surrounding maternal suicide, and it highlights opportunities for further research to understand long-term consequences of perinatal mental health. These findings also underscore the need for targeted evidence-based interventions and effective policies targeting mental health, substance use, and IPPs to prevent maternal suicide and enhance maternal health outcomes.