1 Introduction Homelessness is not solely characterised by a lack of a roof or literal homelessness; it also encompasses insecure, unstable, and inadequate housing [1]. Safe, secure, healthy housing is a crucial determinant of health throughout life [2]. People experiencing homelessness experience high rates of psychiatric disorders, substance abuse, infectious diseases, and premature mortality [3, 4]. No routine data sources are capturing the prevalence of homelessness in pregnancy in the UK.