Background The estimated incidence of a cancer diagnosis during or shortly after pregnancy is 1 in 1000 pregnancies in England. Pregnancy can have an impact on symptom appraisal and help-seeking for symptoms subsequently diagnosed as cancer. Little is known about the pathway to cancer diagnosis in pregnancy or delays that women can encounter. Aim To explore symptom appraisal, help-seeking decisions, and experience of receiving a cancer diagnosis during pregnancy. Design and setting Semi-structured interviews were conducted with women diagnosed with cancer during or shortly after pregnancy in the previous 4 years in the UK, recruited between January and May 2022 via the charity Mummy’s Star. Method This study used reflexive thematic analysis of 20 interviews. Analysis was largely inductive and the themes generated were mapped onto the intervals of the Model of Pathways to Treatment. Results Symptoms were often interpreted through the lens of pregnancy by both participants and most of the healthcare professionals from whom they sought help. Participants who found breast lumps were likely to suspect cancer and be referred promptly for tests in secondary care. Although most participants sought timely help for their symptoms, some subsequently encountered health system delays, partly owing to both the vague nature of their symptoms and the COVID-19 pandemic. Conclusion Health services need to better support women presenting with possible cancer symptoms during pregnancy to ensure timely diagnosis. Recommendations include prioritising symptoms over attributing them solely to pregnancy, ensuring timely referrals to rule out serious conditions, and emphasising clear communication alongside robust safety-netting practices. A full assessment is essential before dismissing symptoms as pregnancy related.