Background Measuring positive and negative aspects of well-being during pregnancy and childbirth is important for both healthy women and women who are living with long-term health conditions (LTCs). This study aimed to further refine the Well-being in Pregnancy (WiP) questionnaire and to incorporate LTC specific items where appropriate. Methods A multi-method study. Cognitive interviews with pregnant or postpartum women (n = 11) and consultations with healthcare professionals (n = 11) and public representatives (n = 4) were conducted to explore the acceptability of existing WiP items and content. Items were refined and subsequently administered on an online survey (n = 768). Item reduction steps and exploratory factor analysis were performed on survey data. Convergent validity was examined using Pearson correlation coefficients to compare relationships with other included validated assessments. Results Following amendments to three items, the addition of eight core WiP items and five LTC specific items, a total of 25 items were considered relevant and appropriate for use with pregnant women. Analysis of survey data reduced the questionnaire to 12 items measuring three core WiP scales; 1) Concerns over support after birth, 2) Positive pregnancy and, 3) Confidence about motherhood, and a five item standalone LTC specific scale. All scales demonstrated good validity and internal reliability. Scores for the three core scales moderately correlated with established well-being measures indicating that they were measuring similar, yet distinct concepts. Conclusions Analyses confirmed good psychometric properties of the refined WiP questionnaire. The use of pregnancy specific well-being measures, such as the WiP, provide a route into asking women in more detail about how their care may be tailored to support them and also facilitates positive conversations with women about how care and experience of pregnancy and childbirth may be enhanced further.