IntroductionThe success of combination antiretroviral therapy has decreased the risk of perinatal HIV transmission and normalised pregnancy in women living with HIV (WLWH). Despite these advances, WLWH still face complex medical and psychosocial issues during pregnancy and postpartum, and there is a gap of knowledge on the experiences of becoming and being a mother living with HIV in today’s context. The overall aim of this study is to investigate psychosocial outcomes and experiences of WLWH in Scandinavia during pregnancy and early motherhood.Methods and analysisThis is a multicentre longitudinal convergent mixed methods study consisting of a quantitative survey study, a qualitative interview study and a mixed methods analysis. The survey study aims to examine psychosocial outcomes of WLWH across the pregnancy – postpartum trajectory. Participants are pregnant WLWH living in Scandinavia. Two control groups of HIV-negative pregnant women and non-pregnant WLWH are also included. Data is collected in the third trimester, 3 and 6 months postpartum using standardised questionnaires. Statistical analysis will assess changes over time and identify predictors of adverse outcomes. The interview study seeks to understand experiences of pregnancy and becoming a mother while living with HIV. Pregnant WLWH who are enrolled in the survey study will be asked to participate in individual interviews in the third trimester and 6 months postpartum. Data will be analysed using narrative analysis. The survey and interview results will be merged in a mixed methods analysis to assess confirmation, expansion or discordance between the data sets.Ethics and disseminationApproval from the Danish Data Protection Agency (VD-2018–253), and the Finnish and Swedish Ethics Committees have been obtained (HUS/1330/2019 and Dnr: 2019–04451, respectively). Study results will be disseminated to patient organisations, through publications in peer-reviewed journals and at scientific conferences.