Objective One in 20 women are affected by pre-eclampsia, a major cause of maternal and perinatal morbidity, death and premature birth worldwide. Diagnosis is made from monitoring blood pressure (BP) and urine and symptoms at antenatal visits after 20 weeks of pregnancy. There are no randomised data from contemporary trials to guide the efficacy of self-monitoring of BP (SMBP) in pregnancy. We explored the perspectives of maternity staff to understand the context and health system challenges to introducing and implementing SMBP in maternity care, ahead of undertaking a trial. Design Exploratory study using a qualitative approach. Setting Eight hospitals, English National Health Service. Participants Obstetricians, community and hospital midwives, pharmacists, trainee doctors (n=147). Methods Semi-structured interviews with site research team members and clinicians, interviews and focus group discussions. Rapid content and thematic analysis undertaken. Results The main themes to emerge around SMBP include (1) different BP changes in pregnancy, (2) reliability and accuracy of BP monitoring, (3) anticipated impact of SMBP on women, (4) anticipated impact of SMBP on the antenatal care system, (5) caution, uncertainty and evidence, (6) concerns over action/inaction and patient safety. Conclusions The potential impact of SMBP on maternity services is profound although nuanced. While introducing SMBP does not reduce the responsibility clinicians have for women's health, it may enhance the responsibilities and agency of pregnant women, and introduces a new set of relationships into maternity care. This is a new space for reconfiguration of roles, mutual expectations and the relationships between and responsibilities of healthcare providers and women. Trial registration number NCT03334149.