Background: Rates of perinatal psychological difficulties (experienced during pregnancy and the twelve-months postpartum) increased dramatically worldwide during the COVID-19 pandemic. In the UK, anxiety and depression were estimated to affect more than half of perinatal women during the first national lockdown. However, little is known about women’s qualitative experiences of distress and the sources of their symptoms. This study aimed to extend quantitative research to qualitatively explore: 1) the psychological symptoms associated with maternal perinatal distress during the COVID-19 pandemic; and 2) the associated psychosocial stressors, in order to guide future preventative and supportive interventions.Methods: As part of an online survey during May 2020, 424 perinatal women completed an open-ended question regarding a recent experience of distress. Qualitative data was analysed using inductive thematic analysis from a realist stance and explored in the context of perinatal anxiety and depression scores.Results: Thematic analysis of the data identified thirteen distinct symptom-related themes of psychological distress. Despite the high rates of probable depression in the sample, women’s descriptions of symptoms were more indicative of anxiety and general distress, rather than those traditionally related to depression. Furthermore, qualitative experiences of distress differed between pre- and postnatal women. In terms of the associated psychosocial stressors, six themes emerged. Three were related to COVID-19, and three described general motherhood experiences unrelated to the pandemic context. Psychological conflict between maternal expectations and the reality of pregnancy and motherhood, and fears surrounding family health, safety, and wellbeing underlay many of the themes. Conclusions: Interventions to support perinatal wellbeing may benefit from a transdiagnostic approach focusing on a multitude of symptoms, particularly those associated with anxiety and general distress. Support should also aim to develop healthy expectations of perinatal experiences, as well as provide psychoeducation to alleviate fears in pregnancy and early motherhood to help reduce maternal distress. This paper also highlights some of the traumatic COVID-related stressors which should be addressed to reduce enduring and recurrent episodes of trauma whilst presenting various opportunities to better support perinatal women should future pandemic restrictions be required.