Background South Africa has a high burden of perinatal common mental disorders (CMD), such as depression and anxiety, as well as high levels of poverty, food insecurity and domestic violence, which increases the risk of CMD. Yet public healthcare does not include routine detection and treatment for these disorders. This pilot study aims to evaluate the implementation outcomes of a health systems strengthening (HSS) intervention for improving the quality of care of perinatal women with CMD and experiences of domestic violence, attending public healthcare facilities in Cape Town. MethodsThree antenatal care facilities were purposively selected for delivery of a HSS programme consisting of four components: (1) health promotion and awareness raising talks delivered by lay healthcare workers; (2) detection of CMD and domestic violence by nurses as part of routine care; (3) referral of women with CMD and domestic violence; and (4) delivery of structured counselling by lay healthcare workers in patients’ homes. Participants included healthcare workers tasked with delivery of the HSS components, and perinatal women attending the healthcare facilities for routine antenatal care. This mixed methods study used qualitative interviews with healthcare workers and pregnant women, a patient survey, observation of health promotion and awareness raising talks, and a review of several documents, to evaluate the acceptability, appropriateness, feasibility, adoption, fidelity of delivery, and fidelity of receipt of the HSS components. Thematic analysis was used to analyse the qualitative interviews, while the quantitative findings for adoption and fidelity of receipt were reported using numbers and proportions.ResultsHealthcare workers found the delivery and content of the HSS components to be both acceptable and appropriate, while the feasibility, adoption and fidelity of delivery was poor. We demonstrated that the health promotion and awareness raising component improved women’s attitudes towards seeking help for mental health conditions. The detection, referral and treatment components were found to improve fidelity of receipt, evidenced by an increase in the proportion of women undergoing routine detection and referral, and decreased feelings of distress in women who received counselling. However, using a task-sharing approach did not prove to be feasible, as adding additional responsibilities to already overburdened healthcare workers roles resulted in poor fidelity of delivery and adoption of all the HSS components.ConclusionsThe acceptability, appropriateness and fidelity of receipt of the HSS programme components, and poor feasibility, fidelity of delivery and adoption suggest the need to appoint dedicated, lay healthcare workers to deliver key programme components, at healthcare facilities, on the same day.