Background: Pregnancy-related anxiety is increasingly recognised as a common condition that is associated with many deleterious outcomes for both the mother and infant (e.g., preterm birth, postnatal depression). Limitations in the psychometric properties and/or breadth of existing scales for pregnancy-related anxiety highlight the need for a psychometrically sound measure to facilitate effective screening and possible early interventions. The recently developed Pregnancy-related Anxiety Scale (PrAS) was evaluated using Rasch analysis to explore how the scale's psychometric properties could be fine-tuned. Method: A sample of 497 pregnant women completed the PrAS. Data were subjected to Rasch analysis, and the resulting scale structure examined using Confirmatory Factor Analysis. Results: After minor modifications, the Rasch model with 33-items and 8-factors demonstrated good fit, unidimensionality and excellent targeting and internal consistency. Confirmatory Factor Analysis confirmed the final structure, and Cronbach's alpha demonstrated excellent reliability. Limitations: The use of the same sample for all analyses was a potential limitation due to the possibility of sample-specific influences. Conclusions: The Rasch analysis further supports the internal construct validity of the PrAS. Ordinal to interval score conversions provide added precision to the analysis of the PrAS scores. The Rasch results, together with previous validation evidence, point to the PrAS as a comprehensive and psychometrically sound screening scale for pregnancy-related anxiety. The PrAS offers clinicians the ability to screen for pregnancy-related anxiety. The subscales provide additional insights into a woman's pregnancy-related anxiety and her specific areas of concern, enabling more targeted interventions.