Objective: to investigate (i) the consistency and completeness of mental health assessment documented at hospital booking; (ii) the subsequent management of pregnant women identified as experiencing, or at risk of, mental health problems; and (iii) women[U+05F3]s experiences of the mental health referral process. Design: mixed methods cohort study. Setting: large, inner-city hospital in the north of England. Participants: women (. n=191) booking at their first formal antenatal appointment; mean gestational age at booking 13 weeks. Methods: women self-completed the routine mental health assessment in the clinical handheld maternity notes, followed by a research pack. Documentation of mental health assessment (including assessment of depression symptoms using the Whooley and Arroll questions, and mental health history), mental health referrals and their management were obtained from women's health records following birth. Longitudinal semi-structured interviews were conducted with a purposive sub-sample of 22 women during and after pregnancy. Findings: documentation of responses to the Whooley and Arroll questions was limited to the handheld notes and symptoms were not routinely monitored using these questions, even for women identified as possible cases of depression. The common focus of referrals was on the women[U+05F3]s previous mental health history rather than current depression symptoms, assessed using the Whooley questions. Women referred to a Mental Health Specialist Midwife for further support were triaged based on the written referral and few met eligibility criteria. Although some women initially viewed the referral as offering a 'safety net', analysis of health records and subsequent interviews with women both indicated that communication regarding the management of referrals was inadequate and women tended not to hear back about the outcome of their referral. Key conclusions and implications for practice: mental health assessment was introduced without ensuring that identified needs would be managed consistently. Care pathways and practices need to encompass identification, subsequent referral and management of mental ill-health, and ensure effective communication with patients and between health professionals.