A review of psychiatric consult notes of 96 obstetric inpatients referred to a Consultation-Liaison (C-L) psychiatry service in a tertiary-level university general hospital was carried out in order to compare the characteristics of such a service in a North American setting with similar services in other parts of the world. Data extracted from consult notes included: reason for referral, current diagnosis (DSM-IV-R), psychiatric history, obstetrical history, recommended treatment approaches, current psychotropic medications, current gestational age or number of days postpartum, patient age, and partnership status. In addition, obstetrical referrals were calculated as a percentage of hospital-wide referrals to C-L psychiatry. The most prominent findings include: (1) a high C-L psychiatry referral rate from obstetrics as a percentage of total C-L referrals within the study hospital; (2) past psychiatric history alone as a prevalent reason for referral; (3) adverse reproductive event (past and/or current) as a common reason for referral. These findings differ markedly in certain ways from comparable studies and may reflect both the hospital's large high-risk pregnancy service that represents an at-risk group for mental health issues, and the focus on educational collaboration with obstetrical staff regarding risk factors for, and consequences of, perinatal mental illness. Inpatient perinatal C-L psychiatric services require creative approaches to the accurate identification and treatment of women at risk for antenatal and postpartum mental illness due to psychiatric history and/or reproductive crises.