The Stirling Antenatal Anxiety Scale (SAAS): development and initial psychometric validation

Abstract

Background Anxiety in pregnancy affects approximately 15% of all pregnant women. Antenatal anxiety can impact negatively on subsequent child development and is a strong predictor of postnatal depression. No anxiety measures with sound psychometric properties are currently available for screening pregnant women. This study aimed to develop and evaluate the psychometric properties of a brief questionnaire specifically devised for use by healthcare professionals and researchers to screen for antenatal anxiety. Methods A mixed-method study for scale development which included: 1) a review examining the psychometric properties of anxiety measures 2) qualitative interviews with women with experience of antenatal anxiety 3) a Delphi study to achieve consensus amongst experts in relation to questions to be included in the scale. For the psychometric validation, 174 women completed the new 10 item scale and the GAD-2/7. A sub-sample of women were also assessed using a diagnostic interview. Results The Stirling Antenatal Anxiety Scale (SAAS) showed very good diagnostic accuracy (sensitivity=91%; specificity=85%). The GAD-2 performed significantly worse (sensitivity=27%; specificity=96% at the recommended cut off-score) than the new antenatal anxiety scale in identifying women with an anxiety disorder. Limitations The key limitation of the research was the relatively small sample size of women assessed with a diagnostic interview for the psychometric validation study. Conclusions Identifying pregnant women experiencing problematic anxiety is the first, crucial step in providing them with an appropriate level of support. This research provides health professionals with a reliable, brief, and easy-to-complete screening scale for anxiety in pregnancy.