Problem: While routine psychosocial assessment is acceptable to most pregnant women, some women will not fully disclose psychosocial concerns to their clinician. Aims: To assess the impact of psychosocial risk, current symptoms and mode of assessment on women's honesty of disclosure at psychosocial assessment. Methods: Logistic regression was used to examine associations between disclosure and a range of psychosocial characteristics in women who were ‘always honest’ and ‘not always honest’. Mixed ANOVAs were used to test the influence of mode of assessment and honesty on scores on a repeated measure of psychosocial risk. Findings: 10.8% (N = 193 of 1788) of women did not fully disclose at psychosocial assessment. Non-disclosure was associated with a mental health history (aOR = 1.78, 95%CI: 1.18–2.67, p < 0.01) and lack of social and partner support (aOR = 1.74, 95%CI: 1.16–2.62, p < 0.05; aOR = 2.08, 95%CI: 1.11–3.90, p < 0.05, respectively). Those reporting not always being honest at face to face assessment showed a greater increase in psychosocial risk score when the assessment was repeated online via self-report, compared to women who were always honest. Discussion: A history of mental health issues and lack of social and partner support are associated with reduced disclosure at face to face assessment. Online self-report assessment may promote greater disclosure, however this should always be conducted in the context of clinician feedback. Conclusion: Greater psychosocial vulnerability is associated with a lower likelihood of full disclosure. Preliminary findings relating to mode of assessment warrant further exploration within a clinical context.