Background Understanding the risk factors for child maltreatment is critical to efforts to reduce its prevalence. Objective This study investigated the association between characteristics and circumstances of mothers during pregnancy and the subsequent identification of concerns about child maltreatment. Participants and setting The study drew on two data sets: (i) data from questionnaires administered to the expectant mothers of 11,332 children born in a deprived multi-ethnic local authority in England between 2007 and 2011, for a birth cohort study, and (ii) administrative data on children referred to child welfare services. Methods The linkage of these two pre-existing data sets enabled the prospective study of risk factors for child maltreatment. Results A range of factors captured during the antenatal period were associated with an increased likelihood of subsequent recorded child maltreatment concerns, including: younger maternal age (HR=0.96; p < .001), lower maternal education level (HR=1.36; p < .001), maternal mental illness (HR=1.17; p = .001), maternal smoking in pregnancy (HR=1.69; p < .001), single motherhood (HR=1.41; p = .022), larger family size (HR=1.13; p < .001), multiple deprivation (HR=1.01; p = .011), social housing (HR=1.72; p < .001), paternal unemployment (HR=1.79; p < .001), and the receipt of means-tested welfare benefits (HR=1.43; p < .001). A greater total number of risk factors during pregnancy also increased the risk of subsequent maltreatment concerns (HR=1.45; p < .001). Conclusions The identification of multiple risk factors in this study supports claims that single targeted interventions are unlikely to be successful in preventing or reducing child maltreatment due to its multifactorial nature, and that multidimensional interventions are required.