BackgroundAlthough associations between maternal exposure to adverse childhood experiences (ACEs) and perinatal anxiety and depression are established, there is a paucity of information about the associations between ACEs and perinatal trauma and perinatal post-traumatic stress outcomes. For the purposes of this article, perinatal trauma is defined as a very frightening or distressing event that may result in psychological harm. The event must have been related to conception, pregnancy, birth, and up to 12 months postpartum.MethodsWomen recruited at an antenatal appointment (n= 262) were invited to complete online surveys at two-time points; mid-pregnancy and eight weeks after the estimated date of delivery. The ACE Q 10-item self-reporting tool and a perinatal trauma screen related to the current and/or a previous perinatal period were completed. If the perinatal trauma screen was positive at either time point in the study, women were invited to complete a questionnaire examining symptoms of perinatal post-traumatic stress disorder and, if consenting, a clinical interview where the Post-traumatic Symptoms Scale was administered.ResultsSixty women (22.9%) reported four or more ACEs. These women were almost four times more likely to endorse perinatal trauma, when compared with those who either did not report ACEs (OR = 3.6, CI 95% 1.74 – 7.36,p< 0.001) or had less than four ACEs (OR = 3.9, CI 95% 2.037.55,p< 0.001). A 6–sevenfold increase in perinatal trauma was seen amongst women who reported having at least one ACE related to abuse (OR = 6.23, CI 95% 3.32–11.63,p< 0.001) or neglect (OR = 6.94, CI 95% 2.95–16.33,p< 0.001). The severity of perinatal-PTSD symptoms for those with perinatal trauma in pregnancy was significantly higher in those women exposed to at least one ACE related to abuse.ConclusionsAwareness of maternal exposure to childhood adversity/maltreatment is critical to providing trauma-informed approaches in the perinatal setting. Our study suggests that routine screening for ACEs in pregnancy adds clinical value. This adds to previous research confirming the relationship between ACEs and mental health complexities and suggests that ACEs influence perinatal mental health outcomes.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12884-023-05714-2.