The prevalence of perinatal common mental disorders in South Africa is high, yet little is known about mental health service use among pregnant and postnatal women. This paper reports on pregnant women's patterns of use of a counselling service at a primary level obstetric facility in Cape Town, South Africa, between January 2010 and December 2011. It investigates whether these are associated with demographics, severity and risk of depressive symptoms. Participants ( N = 3311) were screened for psychological distress using the Edinburgh Postnatal Depression Scale ( EPDS) at their first antenatal visit. Risk factors for antenatal depression were assessed using a 11-item checklist. Questionnaires were self-administered, but some participants required assistance. Participants scoring positive (≥13) on the EPDS were offered referral to on-site, individual counselling, and assigned to one of three groups according to their service use: declined referral; accepted referral and attended counselling sessions; and accepted referral but defaulted all appointments. Consent to participate was received by 3437 (96.4%) participants who were offered screening, of which 627 (18.9%) screened positive on the EPDS. Of these, 363 (57.9%) attended counselling. Both bivariate analyses and regression analyses revealed that age and risk factor assessment score were associated with screening positive on the EPDS. Odds ratios ( OR) for accepting counselling were OR = 0.94 (95% CI = 0.92-0.97) for gestation, OR = 1.27 (95% CI = 1.15-1.39) for EPDS score and OR = 0.48 (95% CI = 0.23-0.99) for reporting three or more risk factors. OR for attending counselling were, for age: OR = 1.06 (95% CI = 1.00-1.12) and for reporting three or more risk factors: OR = 0.60 (95% CI = 0.37-0.97). While the majority of women with psychological distress accessed the counselling service provided, strategies to increase service use of younger pregnant women specifically are required. [ABSTRACT FROM AUTHOR]