The concept of well-being is multi-faceted by encompassing both positive and negative emotions and satisfaction with life. Measuring both positive and negative thoughts and emotions is highly relevant in maternity care that aims to optimise a woman's experience of pregnancy and childbirth, focussing on positive aspects of health and well-being, not just the prevention of ill health. Yet our understanding of well-being in pregnancy and childbirth is limited as research to date has focussed on negative aspects such as stress, anxiety or depression. The primary aim of this study is to describe the psychometric properties of a newly developed Well-being in Pregnancy (WiP) questionnaire.