Pregnancy and childbirth are among the strongest risk factors for depression. Research has consistently highlighted several factors associated with enhanced risk of postpartum depression (PPD), including, previous depression, poor social and emotional support, and pregnancy- and birth complications. In a study of asymptomatic pregnant women with and without a history of affective disorder, we found that negative cognitive bias in the processing of infant signals of emotion predicted subsequent postpartum depression. No existing screening tools for pregnant women that can identify the relative impact of these different factors – or their interaction – on the risk of PPD. The PreScreen study therefore aims to test the feasibility of an online screening tool that integrates multiple risk factors, including negative cognitive bias, and to investigate the predictive validity of this screening tool for subsequent PPD.