Mental health is especially important as women transition into parenthood. The COVID-19 pandemic has necessitated the rapid reconfiguration of maternity services, including perinatal mental healthcare, as offered by Specialist Perinatal Mental Health Midwives, in NHS Trusts in the United Kingdom. This article represents work undertaken in rapid response to the COVID-19 pandemic and aims to document the findings from March 2020 up until May 2021 in literature published on perinatal mental health through the pandemic, as well as to engage in a knowledge mapping exercise across five NHS Trusts in London. In this research, we utilised a critical review methodology which purposefully selects and synthesises materials after extensive literature searching to provide a broad and informed narrative around an issue. For our knowledge mapping exercise, we utilised an inclusive stance to gather, pool, and synthesise data from five NHS Trusts regarding the provisions and reconfigurations of their perinatal mental health services, creating a comparable and translatable snapshot in time. Our rapid, critical review highlighted two themes: ‘Increased Perinatal Distress’ and ‘Inaccessible Services and Support’. Our knowledge mapping exercise produced four themes: ‘Retention of Existing Service Provision’; ‘Additional Services Provided’; ‘Reconfiguration of Service Provision’; ‘Additional Provision to Support Staff Wellbeing’. We conclude by offering best practice guidance in order to provide shared learning to aid the transition through para-pandemic circumstances to service delivery in a post-pandemic ‘new normal’.