Psychological trauma - including exposure to intimate partner violence (IPV) - is highly prevalent in South Africa, and may result in posttraumatic stress disorder (PTSD) in a subset of individuals. Pregnant women and new mothers are particularly vulnerable; and trauma exposure and PTSD in this sub-group may be associated with a number of adverse maternal-child sequelae including poor birth outcomes and impaired infant neurodevelopment. Risk factors for psychological trauma exposure, and for subsequent PTSD, are likely to include environmental and genetic influences. Given the high burden of trauma and related disorders, the unique genetic ancestry, and the relative paucity of empirical data, further work in South African populations is warranted. This thesis aimed to investigate a number of questions about trauma and PTSD in the Drakenstein Child Health Study (an ongoing South African birth cohort study), including their risk factors, their impact on infant birth anthropometry and development, and their genetic correlations. This thesis includes five publications, all presenting data from the Drakenstein Child Health Study. Pregnant women were recruited from two clinics in the Drakenstein sub-district - a peri-urban community outside Cape Town, Western Cape. Sociodemographic characteristics; psychosocial risk factors (including depression, stressful life events, psychological distress and alcohol and substance misuse); trauma exposure (childhood trauma, IPV and lifetime trauma); and PTSD were assessed using validated and reliable self-reported questionnaires, as well as diagnostic psychiatric interviews.