Childhood adversity can have long-term deleterious effects on adulthood mental health outcomes, but more research is needed examining how type and timing of childhood adversity affect mental health specifically during pregnancy. The current study examined the effects of total adverse childhood experiences (ACEs) on depression and posttraumatic stress disorder (PTSD) symptoms during pregnancy, unpacked effects of total adversity into childhood maltreatment versus family dysfunction experiences, and assessed age of onset effects of child maltreatment-specific experiences. Participants were 101 low-income pregnant women (M = 29.10 years, SD = 6.56, range = 18-44; 37% Latina, 22% African American, 20% White, 13% biracial/multiracial, 8% other; 26% Spanish-speaking) who completed instruments on childhood adversity, PTSD and depression symptoms during pregnancy, and demographics. Results indicated that total ACEs predicted elevated PTSD and depression symptoms during pregnancy, as did maltreatment ACEs, but not family dysfunction ACEs. Early childhood onset of maltreatment significantly predicted elevated PTSD symptoms during pregnancy, whereas middle childhood and adolescent onset did not. No age of onset of maltreatment variable significantly predicted depression symptoms during pregnancy. Findings underscore the importance of differentiating between childhood maltreatment versus family dysfunction ACEs and examining the timing and accumulation of maltreatment experiences during childhood, because these factors affect mental health during pregnancy. Findings also support universal prenatal screening for PTSD symptoms to identify at-risk pregnant women who could benefit from interventions to disrupt the intergenerational transmission of risk and give families the healthiest possible beginning. (PsycINFO Database Record (c) 2019 APA, all rights reserved).