The Initial Development and Psychometric Evaluation of the Pregnancy-related Anxiety scale

This dissertation reports on the development and psychometric evaluation of the Pregnancy-related Anxiety Scale (PrAS). The PrAS was developed as a screening scale for the distinct anxiety type, pregnancy-related anxiety that is characterised by pregnancy-specific fears and worries. The need for the development of the PrAS was demonstrated by a critical and comprehensive review of all known scales in current use for pregnancy-related anxiety. This critical examination highlighted the lack of a suitable measure, with the majority of existing scales limited by either a lack of a theoretical foundation or evidence of validity or both.
To provide a stronger theoretical basis for this scale development, the Huizink et al. (2004) study was replicated. Huizink and colleagues demonstrated that pregnancy-related anxiety is a relatively distinct construct from general anxiety and depression. However, to date, there is little evidence of the replication of this study. The replication was completed on two separate occasions with two different samples of pregnant women. Both studies supported the findings from the original Huizink study. On the basis of this, and other similar findings that support Huizink and colleague’s conclusion, a comprehensive literature review was completed. Subsequently, the item pool was developed from this literature review and consultation with the Expert Review Panel. The Expert Review Panel, which consisted of experts in related fields (e.g. perinatal psychologists, psychometricians, and psychiatrists) assisted the assessing and refining the items. The literature review and Expert Review Panel process were both integral to establishing the scale’s content validity.
Assessment of construct validity, for the PrAS, used discriminant measures (e.g. depression and neuroticism) and convergent measures (e.g. pregnancy specific). In addition, evaluation of concurrent validity was through the examination of the scale’s predictive ability through group differentiation (i.e., anxious versus non-anxious pregnant women). Finally, examination of the PrAS’s internal validity used Rasch analysis and structural equation modelling. Rasch analysis enabled further refinement of the scale and provided more focused targeting of the population of interest (i.e. pregnant women). Further, the Rasch analysis, through the ordinal to interval score conversions, brought added precision to the scoring of the scale.
The final 32-item scale demonstrated high to excellent internal consistency reliability and good validity. The PrAS, therefore, is a screening scale that provides clinicians with a comprehensive assessment of pregnancy-related anxiety. Indeed, the PrAS contains subscales not previously seen in existing scales, which provides greater opportunity for more targeted interventions. This focused targeting is effected through individual subscale assessment after the full-scale assessment has occurred. For researchers, the PrAS also provides a comprehensive evaluation of pregnancy-related anxiety by offering greater precision in analysis by the interval scale conversions. The PrAS, therefore, makes a significant contribution to clinical and research settings in the area of pregnancy-related anxiety.